How to handle difficult low-carb cases
It is organized in the following sections:
- Health markers or lab results
Queries about lab tests results for triglycerides, cholesterol/lipids, uric acid, CRP, HbA1c, fasting glucose, fasting insulin, liver enzymes, microalbumin, low blood glucose, high ketones.
- Pre-existing health issues
Queries about patients with pre-existing bariatric surgery, gout, gallbladder issues, kidney stones, fatty liver, pancreatitis, statin prescription.
- LCHF symptoms or side effects
Queries about keto rash, insomnia, cramps, GERD, headache/migraine, hair loss, palpitations, nausea, cold, fatigue/lethargy, bad breath, constipation, diarrhea, menstrual cycle changes.
- Diet compliance or success
Queries about hunger, protein amounts, weight stalls, gaining weight allergies, fat intake, vegetarianism, achieving ketosis, diet during women’s cycles.
- Family, medical, or social supports
Queries about maintaining the diet with non-supportive spouse, health practitioners, children, family and friends, low incomes, busy travel.
Health markers or lab results
On the low-carb, high-fat diet (LCHF) or keto diet most health markers and lab results tend to improve.1 However, for instances where that is not the case, this guide will help you trouble shoot the unexpected results.
- Triglycerides are rising
- Total cholesterol/LDL is rising
- Uric acid is rising
- Inflammatory markers are rising
- Fasting insulin is rising
- Liver enzymes are rising
- Fatty liver has not improved on abdominal ultrasound
- Blood sugar levels are increasing or staying high during the day
- Blood pressure is not improving
1. Triglycerides are rising
Fasting triglycerides (TGs) are expected to go down with an LCHF diet because the body is now using them as energy, replacing glucose as the body’s main fuel. However, TGs are greatly influenced by diet, so they can vary throughout the day.
If triglycerides are rising, first make sure your patient did a water-only fast for 10-14 hours prior to the blood test. Next, check for alcohol consumption and confirm that they are truly compliant with the low-carb diet (check for “carb creep”). In very rare cases, this may be due to a genetic disorder such as familial hypertriglyceridemia.
If there is no clear explanation, inquire about coffee consumption. Anecdotally, some have noticed an increase in TGs with coffee consumption on a low-carb diet. While it is not known if this is a clinical concern, stopping the coffee appears to normalize the TGs.
After the above intervention, retest in 3 months (sooner if TGs are >500 mg/dl).
2. Total cholesterol/LDL is rising
A low-carb, high-fat diet usually improves cholesterol profiles.2
Typically HDL cholesterol increases while triglycerides decrease and LDL particles become larger and less dense.3 All three of these changes statistically reduce the risk of future heart disease.
However, in some cases the LDL cholesterol might go up on a low-carb or ketogenic diet. Sometimes the increase is not significant; other times, especially with lean people, it can increase substantially. And frequently it is a transient rise that normalizes over time.
However, LDL by itself may not be as strong a risk factor for cardiovascular disease as lipid ratios, and in the absence of diabetes or metabolic dysfunction. Therefore, LDL increases need to be put in context with other risk factors before deciding if medications or dietary changes are warranted. We recommend using a comprehensive cardiovascular risk assessment rather than reacting to a single lab value change.
Read more about cholesterol on a low-carb diet in our evidence-based guide Low-carb cholesterol basics.
Short answer: Retest in 3 to 6 months.
On average, the elevation of total and LDL cholesterol is so small that most studies do not even pick up on it.
One study found patients who followed a low-carb, high-fat diet for two years showed a reduction of atherosclerosis, with fewer signs of heart disease.4 However, potential problems exist, albeit rarely.
A smaller number of people – estimated as between 5 and 25% percent of the population – have dramatic elevations of LDL and total cholesterol. Take this potential risk seriously and consider steps to correct it.
For example, a small subgroup of people can end up with total cholesterol over 400 mg/dl (10 mmol/l) on a strict low-carb diet, and LDL cholesterol over 250 mg/dl (6.5 mmol/l). Even if the lipid profile is otherwise good – with high HDL and low triglycerides – we do not have conclusive evidence that extremely high cholesterol levels are safe.
If the LDL particle count is high and the apoB and apoB/A1 ratio values abnormally high, these may indicate an increased risk of heart disease. The guidelines are clear that treatment is warranted in such cases. Until we have clear evidence that this is not a concerning scenario, we suggest defaulting to the guidelines when discussing risk and benefit with your patients.
What can be done to prevent or minimize the impact?
If this scenario occurs in your patients, advise them to do the following, in this order:5
- Stop drinking bulletproof coffee: If patients stop drinking fat — such as butter, coconut oil or MCT oil in coffee, or drinking other fats when not hungry — this alone can often normalize LDL cholesterol levels.
- Eat only when hungry and consider adding intermittent fasting to their daily routine (IF often reduces cholesterol levels).
- Use more unsaturated fats like olive oil, fatty fish and avocados instead of saturated fat. Whether it will improve their health is unknown, but it will lower their cholesterol.
- Consider whether the patient really needs to be on a strict LCHF diet. A more moderate or liberal LCHF diet (about 50–100 grams of net carbs per day) can still achieve good results and will likely lower their cholesterol. If they decide to increase their carbs, recommend minimally processed carb sources, such as sweet potatoes, fruit, and nuts, rather than a resumption of eating wheat flour or refined sugar.
Should you prescribe a statin?
When cholesterol is high, and especially for people with preexisting heart disease, the question of cholesterol-lowering medication — typically statins — is often discussed. Statins do lower the risk of heart disease, but at the risk of side effects, like reduced energy, muscle pain and an increased risk of type 2 diabetes.
For people with preexisting heart disease, the relatively modest risk of side effects is often outweighed by the benefits. For people without heart disease, it’s less clear. See the section below, History of statin use, for more information.
3. Uric acid is rising
Serum uric acid levels can go up in the first few weeks of starting a low-carb diet, but they usually normalize by weeks 6-8.6 Just because some people naturally have a higher uric acid level doesn’t necessarily mean they will develop gout. This is especially true of those without a prior history of gout.
See our section on gout below.
Retest in 2-3 months if necessary.
4. Inflammatory markers are rising
Many factors can influence the results of the c-reactive protein (CRP) or high-sensitivity-CRP (hs-CRP) test. Infections and even a simple cold can increase this marker, as can food intolerances, poor sleep, or an intense workout. Look for other causes, and repeat if necessary in 3-6 months.
If there is no alternative reason and no improvement in inflammatory markers, you could consider reducing saturated fat, especially bulletproof coffee and processed meats, to see if this is a potential trigger.
5. Fasting insulin is rising
Fasting insulin levels are influenced by stress, fatigue and other factors, so rising levels are not a direct indicator of insulin resistance. Interpret these results in the context of other markers of insulin resistance, such as fasting glucose, postprandial glucose, and HBA1c.
Retest in 3 months, or do a 2-hour postprandial insulin to get a more detailed picture of the situation. Even better, see if your patient can access a continuous glucose monitor (CGM) for the most accurate information.
6. Liver enzymes are rising
Liver enzymes, measured by the alanine aminotransferase (ALT) test , can go up in the first few weeks of switching to a low-carb diet or with significant weight loss. Eventually, they almost always go down.7
If ALT does not go down or even increases after a few months and weight is stable, check for diet compliance and explore other causes such as alcohol consumption or non-diet related causes.
7. Fatty liver has not improved on abdominal ultrasound
Accumulating evidence shows that low-carb diets are an effective treatment for fatty liver. However, the benefits may not be seen immediately, and may take up to a year. Therefore, as long as there is no progression of fatty liver, we suggest continuing to monitor at 6- to 12-month intervals.
Emerging evidence also suggests intermittent fasting may be a powerful adjunctive treatment for fatty liver.8
8. Fasting blood sugar levels are elevated
Higher blood sugars are commonly seen in the morning with patients on low-carb diets. This so-called “dawn phenomenon” is thought to occur from the early morning cortisol rise that increases glucose secretion from the liver. We recommend having the patient check pre- and post-prandial blood glucose levels, and if possible consider a CGM. If the glucose levels are optimal the remainder of the day and the HgbA1c is not a concern, then no intervention is required.
If blood sugars remain high, ask the patient to keep a food journal and check for hidden carbs, excess protein, snacks, and drinks, including alcohol. Focusing on time-restricted eating and intermittent fasting can sometimes help in this situation.
In rare cases, a rising blood glucose or HgbA1c despite a low-carb diet could be a sign of latent autoimmune diabetes in adults (LADA). In this case, check a C-peptide and consider consultation with an endocrinologist for definitive diagnosis.
9. Blood pressure is not improving
Most people who adopt a low-carb diet will see their blood pressure decrease, but a few will find their blood pressure remains elevated or even rises.
Consider non-food-related causes such as increased stress or poor sleep. Also, evaluate the patient’s sodium intake. While most people can safely increase their salt intake on a low-carb diet, a small subset may be salt sensitive and experience an increase in blood pressure. A trial with lower sodium intake may be indicated.
See our evidence based guide on salt for more information.
Pre-existing health issues
In general, low-carb and keto diets are safe for most individuals. However, there are a couple of exceptions. Patients with advanced renal disease who are not yet on dialysis need low-protein diets that are largely incompatible with carbohydrate restriction. It’s not that it can’t be used, but it is enough of a challenge that we do not recommend it.
Certain rare disorders of fat metabolism are also contraindications to very-low-carb diets. These include carnitine palmitoyltransferase (CPT) deficiency; short-chain, medium-chain or long-chain acyl dehydrogenase deficiency (SCAD, MCAD or LCAD); and pyruvate carboxylase deficiency. Fortunately these are very rare conditions that are usually diagnosed at a young age. Therefore, it is unlikely an adult patient would present without a pre-existing diagnosis of these severe fat metabolism disorders.
From a lipid standpoint, hyperchylomicronemia is a contraindication due to the body’s inability to properly handle the products of fat digestion. This likewise usually presents early in life, and it is rare to encounter a new diagnosis as an adult.
Finally, in some cases patients with an acute, unstable medical condition — such as acute pancreatitis, active liver failure, acute gout, and others — are not candidates for this dietary intervention. The acute condition should be resolved before therapeutic carbohydrate restriction is considered.
Other conditions, as detailed below, may require special attention but do not preclude the use of carbohydrate restriction
- History of gout/hyperuricemia
- History of gallbladder issues
- History of kidney stones
- History of bariatric surgery
- History of statin use
1. History of gout/hyperuricemia
Can patients with a history of gout do the LCHF diet? Yes, definitely, but they may be at increased risk of a gout flare in the first six to eight weeks.9 Therefore, patients with a history of gout may need prophylactic treatment with allopurinol during the initial stages of carbohydrate restriction.
Over the long term, uric acid levels tend to decrease on low carb, along with other markers of metabolic syndrome. One study showed uric acid going down significantly after 6 months on low carb.10 This suggests it may decrease the risk of gout. There is also preliminary evidence that the ketone body beta-hydroxybutyrate (BHB) may directly reduce gout flares.11
Will the LCHF diet precipitate gout in some patients without a history of gout?
While short-term studies show a temporary rise in uric acid during the first few weeks of starting a strict low-carb diet, doctors regularly treating patients with low-carb diets typically do not notice an increase in gout episodes. Any increase in risk during the first few weeks is likely small or moderate, with uric acid soon returning to baseline or even lower.12
Clinical observations from low-carb physicians:13
- Almost all uric acid levels return to normal within six to eight weeks.
- Patients who have a previous history of gout are the most at risk for developing a gout attack in the first 6-8 weeks. Adjust medications accordingly or discuss prophylaxis if necessary.
- Patients who do not have a history of gout will likely not experience it even if their uric acid levels go quite high.
What else can be done to prevent or minimize a gout flare?
Along with medication support, as stated above, doctors can encourage their gout patients to:
- Minimize sugar intake: Gout is strongly related to obesity, type 2 diabetes and metabolic syndrome, so consumption of sugar and refined carbohydrates may be at its root.14 High blood levels of insulin have been shown to increase uric acid levels, probably by reducing excretion of uric acid by the kidneys.15 Moreover, gout epidemiology parallels populations’ sugar consumption (for example, 18th Century Britain, at the birth of its sugar industry). Fructose consumption is also strongly linked to uric acid levels 16
- Reduce alcohol consumption: Beer and other high-carb alcoholic beverages are of particular concern, but all alcohol consumption should be minimized.17
- Drink water with lime or lemon: Add 1-2 tbsp of unsweetened lime or lemon juice to water throughout the day in the first 6-8 weeks of LCHF. One small pilot study showed citric acid can neutralize uric acid and may reduce uric acid levels.18
2. History of gallbladder issues
Traditional medical advice is that a diet high in fatty foods can predispose patients to the creation of gallstones, gallbladder attacks, and even the eventual need to remove the gallbladder.
Does this mean patients with a history of gallstones or gallbladder removal (cholecystectomy) cannot eat a low-carb, high-fat diet? No, not at all.
In fact, evidence is mounting that a diet low in fat and high in carbohydrates may increase the risk of gallstones.19 The theory is a low-fat diet causes bile to sit idle in the gallbladder rather than being released at regular intervals for dietary fat digestion, triggering the creation of stones. Several studies have confirmed the link between low-fat diets and gallstones.20
After stones are formed, when a higher-fat food is then consumed and bile released from the gallbladder, the stones can get stuck in the bile duct. This typically causes extreme pain in the top-right portion of the abdomen, radiating to the back.
What doctors need to know
The following advice may help your patients with gallbladder issues on a LCHF diet:21
- Asymptomatic patients: If stones have been visualized or confirmed but the patient has no symptoms, there is no need to do anything. Their stones may never be an issue.
- Symptomatic patients: If they experience severe pain after eating low-carb or keto meals, they may need to reduce their lipid intake or break it up into smaller portions throughout the day. In theory coconut oil and MCT oil may help as they do not stimulate bile release. However, this is anecdotal, without a clear consensus. If these methods do not reduce attacks they may eventually need to have elective surgery or be placed on specific drugs to manage their stones.
- Patients without a gallbladder: An LCHF diet can be consumed when the gallbladder has already been removed, but patients may need to eat smaller, more frequent meals with smaller amounts of fat at any one time, at least in the beginning. The liver still makes bile to digest the fat, but the gallbladder can no longer concentrate and store it. Bile is released directly into the intestine. Consuming low-carb, above-ground vegetables or keto bread with meals may help slow digestion of the fat and slow down diarrhea. There is also inconsistent anecdotal evidence that an ox-bile supplement can help break down fats and reduce diarrhea or other digestive symptoms.
Will LCHF improve or dissolve gallstones?
No formal study has yet tested an LCHF diet on people with gallstones.
However, anecdotally, many people report having their gallstone symptoms eventually disappear on a LCHF diet, sometimes after an initial gallstone attack.
3. History of kidney stones or kidney disease
Excess salt can be a concern for increased risk of kidney stones. Some but not all people starting a LCHF or keto diet may need to increase their salt intake to reduce the symptoms of induction or keto flu. However, as far as we know, research to date has not found that kidney stones occur more often among those who follow a low-carb or ketogenic diet.22
Instead, most reports of kidney stones are anecdotal — primarily on internet forums — from adults who claim they developed a kidney stone soon after starting a low-carb diet. However, since kidney stones are very common — occurring in 10% of all men and 7% of women in the US, the majority of whom are on a standard American diet — the timing of a stone forming might have had nothing to do with starting low carb.
If kidney stones do form while following a low-carb diet, make sure your patient stays well hydrated and avoids large amounts of high-oxalate foods such as caffeine, chocolate, spinach, okra, Swiss chard, and rhubarb.
Regarding kidney dysfunction, studies have shown no significant risk with moderate or high protein intake in the absence of pre-existing kidney disease.23 Therefore, low-carb diets are likely safe for all except those with advanced kidney disease.
For more details, see our evidence-based guide What you need to know about a low-carb diet and your kidneys.
4. History of bariatric surgery
Increasingly, more patients are coming to the LCHF diet after having had bariatric surgery. Of course, it is preferable that patients attempt a trial of the diet before life-altering surgery, as it may remove the need for surgery completely. However, post bariatric surgery, an LCHF or keto diet can be a valuable, even essential, addition to long-term success and permanent weight loss and diabetes reversal.
Avoidance of carbohydrates and adherence to a strict LCHF or ketogenic diet may remove the strong cravings, sugar addiction and compulsion for binge eating that may underlie patients’ past struggles with obesity.24
Patients who have had bariatric surgery can safely fast, but they should avoid eating one large meal in a restrictive eating window. They can still restrict their eating window, but it is better for them to graze over a 6-hour restricted time period rather than eat two larger meals within a 6-hour window. 25
Increasingly, evidence is showing that carbohydrates are highly addictive substances that release endorphins and provide pleasure and significant but often dysfunctional emotional regulation.26 In fact, many recent studies show a strong risk for addiction transference from food to other substances, such as alcohol and gambling, in patients after bariatric surgery.27
In addition to following an LCHF or ketogenic diet, long-term success of bariatric surgery patients may require that doctors address their emotional triggers for eating carbohydrates and other foods. These include helping them deal with feelings of anxiety, stress, depression, anger, fear, pleasure, boredom and other uncomfortable emotions that they may have self-medicated with carbohydrates.
5. History of statin use
If your patient is taking a statin, should that affect your decision to prescribe a low-carb diet? Definitely not. In fact, many doctors see a statin combined with a low-carb diet as an effective way to treat patients at high risk for heart disease, as the combination can improve diabetes, metabolic disease, obesity and lower the LDL all at the same time. 28
In fact, one study showed an overall reduction in the 10-year cardiovascular risk calculation after just one year on a low-carb diet.29 The natural increase in HDL, decrease in TGs, improvement in blood pressure and improvement in diabetes may lower your patient’s risk enough that a statin is no longer warranted.
As with any medication, continuing or stopping it requires a detailed evaluation of the potential risks and benefits of the medications compared to alternatives. For instance, recent guidelines recommend a coronary calcium score for those at intermediate risk of heart disease.
This Diet Doctor guide can help you evaluate cholesterol within the context of a low-carb diet:
And this Diet Doctor guide can help you and your patient re-frame the risk-benefit analysis:
LCHF symptoms or side effects
- Keto rash
- Muscle cramps
- GERD arises or worsens
- Feeling cold
- Lethargy and fatigue
- Hair loss
- Bad breath
- Changes in female patients’ menstrual cycles
1. Keto rash
Occasionally patients new to low-carb or ketogenic diets experience an intense, itchy, usually symmetrical rash. It is most commonly observed on the back, under the armpits, and around the neck, shoulders, chest and breast tissue. Sometimes the arms and legs are affected as well.
While relatively uncommon, it is highly annoying, distracting and distressing for those who experience it.
Why does it occur?
Theories abound about the root cause of this problem, but scientific data is very limited as to why it happens.
The common progression of the rash is:
- The itching usually starts soon after patients enter ketosis. It stops within a day or so if they eat more carbs and exit ketosis.
- It can often get worse in hot weather, or after exercising.
- The usual distribution of the itch and rash matches areas where sweat can accumulate.
This progression supports the notion that the itching may be caused by the ketones in sweat drying on the body, especially acetone, which can be irritating in high concentrations.
What to recommend to patients to prevent or minimize the impact
- Reduce sweating: Wear comfortable loose clothing for the climate and use air-conditioning when appropriate.
- Shower: Rinse the body well after exercise or on hot days to remove any irritants.
- Change exercise plans: Skip exercise for a few days or do something like brief weight training that does not produce perspiration.
- Exit ketosis and gradually re-enter: Allow the body to adapt more gradually to ketosis, by slowly lowering carb intake. See the apple cider vinegar protocol below .
- Stay out of ketosis: Exiting ketosis will reliably cure the issue within a day or two. To still get benefits of LCHF – at least for weight loss and type 2 diabetes reversal – patients can do a more liberal low-carb diet (50-70 grams of carbs per day) and add intermittent fasting.
- Other treatments: There are many other treatments suggested online, such as antibiotics taken for weeks or months and/or special creams. We do not advise treating with oral antibiotics, as the side effects and risks are much worse than the dubious and temporary benefits. Steroids, anti-fungal creams and anti-histamines appear not to be effective at all.
Some believe the keto rash is a result of candida die-off. Again, little scientific data supports this claim, but there is the possibility of developing fungal infections in these areas that become sweaty and itchy.
Apple cider vinegar protocol for the keto rash
Some low-carb physicians have found advising patients to consume raw, unfiltered apple cider vinegar internally and apply it externally can help. This protocol may help patients clear a keto rash within 2-5 days and then get back into ketosis within 2 weeks without the rash reappearing or fungal infections developing:
- Use raw, unfiltered (cloudy) apple cider vinegar (with the “mother,” meaning the probiotic culture that is part of fermentation.)
- Internal use: Add 2 tbsps to 1 cup water and drink. Do this 3 times a day for two weeks and then reduce to 1 tbsp of vinegar in 1 cup of water 3 times a day for another two weeks.
- External use: Mix equal parts vinegar and water and apply topically to the affected area twice a day for two weeks. Leave on for 15-30 minutes before rinsing off.
- Consume strawberries, raspberries and/or blackberries.
- Consume 1 cup of berries per day for one week.
- Reduce the berries to ½ cup per day for a subsequent week
- Eliminate berries and continue with the raw, unfiltered apple cider vinegar, as above.
- Take a good-quality probiotic
2. Muscle cramps
Some people experience increased muscle cramping, particularly at night, on a low-carb or keto diet.
Patients should drink plenty of fluid and consume enough salt. Once sodium levels drop too low, the body may experience changes in the other electrolytes, namely magnesium and potassium. The first line of muscle cramp prevention is to make sure sodium levels remain stable.
Second, suggest magnesium supplements. Many patients, formerly fueled by carbohydrates, are magnesium deficient at the start of an LCHF diet, but this can be exacerbated if sodium intake is too low.
Recommended magnesium supplementation
- Magnesium bisglycinate (glycinate) or malate, 400 mg once a day to start, for patients who are prone to diarrhea or loose bowel movements, and/or for patients who also have chronic pain.
- Magnesium citrate, 400 mg once a day to start, for patients who are prone to constipation.
- Daily Epsom salt baths or foot soaks: dissolve 1-2 cups of Epsom salt (magnesium sulfate) in a bathtub or 1 cup in a foot soak. Soak for 15-20 minutes daily (or as often as possible) for the first 3 weeks or anytime muscle cramping arises.
- Magnesium oil/gel: This can be purchased at a store or made at home and massaged into leg muscles. Homemade recipe:
- Bring 1 cup of distilled water to a boil.
- Dissolve 1 cup of Epsom salt or magnesium sulfate into the boiling water and let the salt dissolve.
- Once dissolved, let cool and then store in a bottle or spray bottle.
If muscle cramps continue, verify the dose, method, and regularity of magnesium supplementation. Increase the dose if necessary. If the increased dose results in loose stools, change the type of magnesium (bisglycinate has less impact on the GI tract), and/or split the doses between morning and night.
3. GERD arises or worsens
Gastroesophageal reflux disease (GERD) usually improves with a low carb or keto diet. However, some patients experience heartburn or indigestion in the first few weeks. This rarely occurs in people who have no history of reflux.
Inquire whether the patient abruptly stopped their PPIs, if they are drinking more coffee than usual (especially on an empty stomach), or if they have been recently using NSAIDs or other drugs that can irritate the stomach.
What patients can do to minimize the impact
- Take their PPI medications as prescribed, even on fasting days.
- Consume raw, unfiltered apple cider vinegar. Add 2 tbsps to 1 cup water and drink. Do this 3 times a day for four weeks and then scale back to 1 tbsp of vinegar in 1 cup of water 3 times a day for another two weeks. This can be done prophylactically or to treat the onset of reflux.
- Drink lemon or lime juice in water. Citric juice is very alkalizing in the gut and can help neutralize stomach acid. Taking 1-2 tbsp in a glass of water a few times throughout the day can help prevent or treat reflux.
Some patients experience irregular or higher than usual resting heart rates. Palpitations can be due to dehydration and lack of salt.
Advise patients to drink enough water to stay hydrated and take enough salt. When carbs are reduced, less insulin is circulating, which means less retention of water and sodium.
Make sure patients are not deficient in magnesium; suggest supplementation if necessary.
If adding salt and water or supplementing with magnesium does not completely eliminate heart palpitations, cortisol being released to maintain blood sugar levels could be the issue. This is usually a temporary problem as the body adapts to a lower-carb diet, and should go away within a week or two.
Antihypertensive medications may need to be reduced. Hypertension can often dramatically improve within the first few weeks of switching to low-carb. Decrease or discontinue diuretic medications first, which should help with palpitations.
In the uncommon situation that the problem persists – and the palpitations are bothersome to the patient – recommend they slightly increase their daily carb intake by 10-20 grams. Then, if heart rhythm normalizes, have them slowly reduce daily carb intake by 5 grams every two weeks. This will reduce the effect of the low-carb diet temporarily by gradually transitioning the body to burning ketones.
5. Feeling cold
Some patients feel cold when they switch from burning glucose to burning ketones, especially when fasting. This is normal.
Recommend that these patients take an extra 15-30 grams of fat a day, which is approximately 1-2 tbsp of olive oil or coconut oil. This will help preserve their metabolic rate during this period of transition and speed up the fat adaptation process.
This does not usually last longer than two months. Patients often report experiencing coldness at first, then suddenly intense feelings of warmth a few months later. This is a sign that the patient has become fat adapted. The patient at this point should stop consuming any extra fat, and resume eating to satiety.
6. Lethargy and fatigue
Fatigue is another symptom that may be due to lack of sodium and water. Patients tend to be scared to consume salt in excess of standard recommendations (around 2 grams per day).
On a low-carb or keto diet, especially in the transition period, the body requires more sodium and water to compensate for increased diuresis caused by a drop in insulin levels. Insulin tells the kidneys to retain water and salt. If less insulin is circulating, the kidneys will start flushing out more water and more salt, which must be replaced.
Fatigue may also occur in patients who have reduced their carb intake but not added enough fat to their diet. Many people understand the concept of a low-carb diet intellectually but have a hard time eating more fat, due to long-standing fear of fat.
Other reasons for lethargy and fatigue could be:
- Magnesium deficiency: See the section on muscle cramps for magnesium supplementation advice.
- Vitamin D deficiency: Suggest supplementation with 1000-2000 IU vitamin D3 and 15 minutes of sun exposure (without sunscreen) a day.
- Anemia (iron or B12 and/or folate deficiencies), especially if the patient is vegan, vegetarian, chronically on PPI’s, or post bariatric surgery.
- Poor sleep: Some patients report having sleep disturbances when they go keto. This is usually temporary and disappears in time and with magnesium taken at bedtime. See the next section on insomnia.
After switching to a low-carb diet, some people experience disrupted sleep. The main reasons are:
- Dehydration: Increased salt and water can help.
- Low magnesium: A magnesium supplement at night can improve relaxation and sleep.
- Excessive energy: Some patients experience such a surge of energy with a low-carb diet, they feel revved up at night. This will improve with time, usually within 2-4 weeks. Meditation can also help, such as through downloadable smart phone apps.
Insomnia during intermittent fasting
Occasionally patients report difficulty sleeping if intermittent fasting is part of their routine. While this only lasts for the first 2-4 weeks of IF, it can be frustrating, tiring and undermine success.
Why it happens
During fasting the body produces adrenaline. Patients often find themselves wide awake when they would rather be sleeping. The body learns to adapt to this increase in adrenaline if the patient continues to fast consistently. Stopping and starting the fasting because of sleep disturbances or life circumstances that interrupt regular fasting often prevents adaptation.
How to prevent or minimize the impact
- Fast consistently. This will allow for the body to adapt to the higher adrenaline levels.
- Be patient. This will almost completely resolve with two weeks. Encourage patients to start fasting during a non-stressful time.
- Take a magnesium supplement. Magnesium has the opposite effect of adrenaline on cells. Magnesium bis-glycinate or malate taken 3-4 hours before sleep is best for patients who are prone to diarrhea or loose stools. Magnesium citrate is best for patients who are prone to constipation. Start with 400 mg once a day a few hours before sleep, because it takes time for the magnesium to be absorbed by the body.
- Take an Epsom salt bath or foot soak in the evening before bed. Transdermal magnesium will have a much more rapid effect than oral supplementation. It can also have other calming and stress reducing effects on the patient.
Changing diets usually means a change in the microbiome, and some changes in bowel habits and regularity might occur.
If patients complain of constipation, make sure they’re drinking plenty of water and consuming enough salt. Magnesium supplementation can also be beneficial, particularly magnesium citrate.
Extra fibre may also help. Advise patients to eat a pudding made with chia seeds soaked in coconut cream, or take 1 -2 tablespoons of psyllium husk with water, ground flaxseeds, coconut cream, and MCT oil 1-3 times a day.
Diarrhea can also happen, especially in the following situations:
- When people are not used to eating a lot of fat or when they are consuming MCT oil. Added fat, especially MCT oil, may need to be started in small quantities (about 1 teaspoon per day for MCT oil) and gradually increased.
- Using a lot of sugar alcohols — such as the sweeteners erythritol, xylitol, mannitol, and sorbitol —in low-carb baking, treats or drinks.
- Drinking large quantities of broth or coffee, particularly during a fast.
Diarrhea should resolve by itself after a few days of adaptation. If it doesn’t and it’s not caused by an identifiable agent, suggest patients try adding psyllium, ground flaxseeds or chia seeds to their diet (1 or 2 tablespoons, 1-3 times per day).
Nausea may be caused by a lack of salt and water or by a sudden and significant increase in fat consumption, especially in someone used to eating a very low-fat diet.
A change in medication, such as adding metformin, can cause nausea. Exogenous ketone supplements and MCT oil may also cause nausea in some people.
Importantly, if your patients experience nausea and are diabetic, check their blood glucose and ketone levels.
Headaches usually occur as part of the keto flu, when transitioning from burning glucose to burning fat. However, they may occur anytime due to lack of salt and water, excessive coffee consumption and stress. Adding a few shakes of salt to a glass of water can often relieve a headache within 10-15 minutes.
12. Hair loss
Temporary hair loss can occur for many different reasons, including major dietary changes, especially ones involving rapid weight loss and/or severe caloric restriction. While LCHF does not restrict calories, temporary hair loss can still take place.
If it happens, it is usually around 2-6 months into the patient’s new way of eating and tends to last about 3 months. Eventually the hair grows back.
To reduce hair loss, make sure patients are eating enough calories and have adequate fat and protein intake. Suggesting that patients increase their protein by about 10-20 grams per day may help, and may also improve weight loss and reduce stress.
If that doesn’t seem to help and the problem persists despite adequate calorie and protein consumption, it could be due to:
- Unusually demanding physical exercise
- Breast feeding
- Nutrient deficiencies
- Psychological stress
Hair loss because of pregnancy and breastfeeding usually resolves with time. Other issues, related to mental and physical stresses, may need to be addressed by other methods.
13. Bad breath
People often report experiencing a strange taste in their mouths or foul breath once they start a strict low-carb diet and go into ketosis. This is caused by increased levels of of the ketone body acetone, and the taste or smell is often described as fruity or reminiscent of nail polish remover. Reassure your patients that this is actually a good sign: confirmation that their bodies are burning fat.
This doesn’t happen to all people who switch from carb-burning to fat-burning. It usually lasts for only a week or two until the body adapts and stops “leaking” ketones through breath and sweat.
Occasionally, this bad breath persists throughout their weight-loss journey. Patients may also develop a harmless white film on their tongue.
How to minimize the impact
For patients concerned with bad breath, suggest the following actions:
- Drink plenty of fluid and consume enough salt. A dry mouth means less saliva to wash away bacteria. Stay well hydrated.
- Maintain good oral hygiene. Brush and floss teeth regularly. For example, higher meat consumption can mean more meat gets stuck in teeth. While good oral hygiene won’t stop the fruity smell since it comes from the lungs, it will reduce other causes of bad breath.
- Use a breath freshener regularly. This can help mask the odour.
- Give it time. The odor will likely reduce in 2-4 weeks of regular ketosis.
- Reduce the degree of ketosis. If the smell is a long-term problem that is creating significant personal distress, introduce a few more carbs into the diet. Usually 50-70 grams per day is enough to drastically reduce the degree of ketosis or take the patient out of ketosis entirely. Then gradually have them get back into ketosis by reducing carbohydrates by about 5-10 grams per week every 2 weeks.
- Try oil pulling. Swirling a tablespoon of olive oil or coconut oil in the mouth can increase lubrication and cleanse the mouth of odorous bacteria. Swish it around and “pull” it through the teeth. Do not swallow. After 15 to 20 minutes, spit it into a garbage can, not down the sink (it may clog drains.) Then rinse with salt water and brush teeth.
14. Changes in female patients’ menstrual cycles
Changes in the menstrual cycles are frequent at the start of LCHF or keto eating. Some women, especially those with polycystic ovarian syndrome (PCOS), even start experiencing regular menstrual cycles for the first time in many months or years.
Some women may experience irregular cycles in the first few months of starting LCHF. This usually resolve on its own.
For women with PCOS and previous irregular cycles or even infertility, caution patients that their fertility might increase suddenly on a low-carb diet. They may need to use more consistent contraception if pregnancy is not wanted.
Diet compliance or success
- Weight is stalling or increasing
- Allergy to nuts
- Female patients with cycle-related weight gain
- Ketosis cannot be obtained or maintained
- Patient is vegetarian
- Patient is fat phobic
- Patient’s ketone levels are high
1. Weight is stalling or increasing
Weight can fluctuate by 2 or more pounds from one day to the next simply from fluid retention. A temporary weight gain does not mean your patient is gaining fat. Remember that the scale is not the best indicator of success. Waist circumference or how clothes fit are usually better ways to evaluate progress.
However, if the weight is definitely increasing without a reduction in waist circumference, ask your patients about the following potential problem areas:
- Eating snacks between meals. Encourage them to eat 2-3 meals per day without snacks. They can increase protein and fat at meals to keep full and reduce snack cravings.
- Consuming lots of nuts, dairy or excessive fat. Eliminating snacks will help, as will removing added fat from coffee or tea.
- Eating close to bedtime. Recommend eating the last meal at least 3 hours before sleep. Adhering to time-restricted eating helps with this.
- Drinking daily alcohol. Encourage patients to stop drinking or switch to low-carb alcohol options.
- Consuming too much or too little protein. Too little can stimulate hunger, and too much can increase calories and potentially gluconeogenesis. Optimal protein intake is likely in the range of 1.2-1.7 g/kg of lean body mass per day.
- Eating beyond satiety. Advise patients to eat slowly, start with small portions, wait to register hunger signals, and only go for second helpings if hunger pangs persist.
- Chronic stress or inadequate sleep. Encourage meditation, stress reduction, and better sleep hygiene.
See Diet Doctor’s tips for losing weight.
The first question is, is this really hunger? Sometimes we mistake hunger for what is really stress, boredom, cravings, or simply because others are eating or the clock says it’s supper time. Sometimes we feel hunger when we are actually thirsty, anxious or tired.
If it is truly hunger, often your patient is not eating enough fat.
Encourage hungry patients to increase fat intake at meals, making sure they are satiated at the end of the meal. If they are struggling with time-restricted eating or intermittent fasting, it may be too soon for them. They should go back to eating three meals per day for a couple of weeks and then try TRE or IF again.
Remember that for decades we have been taught to avoid hunger. Most people will need time to understand their hunger cues and realize they don’t always have to act upon them.
Protein amounts are confusing
Protein recommendations can differ between practitioners and specific needs of individual patients. However, despite apparent differences, protein consumption for most patients should remain moderate, between 1.2 to 1.7 g/kg of lean mass per day.
It is always best to have a rough idea of your patient’s body composition since protein goals are based on lean body mass and not total weight. If it is not possible to obtain that information from a DEXA scan, hydrostatic weight or other reliable method, then use the patient’s reference body weight in kilograms to calculate protein needs.
If a patient is sedentary, aim for the lower end of the spectrum. If the patient is active, recovering from sickness or surgery, or elderly with sarcopenia, it may be better to aim for the higher range of protein. The key is to not have them go too much above or below the reference range.
One of the main concerns with protein is that it can stimulate the production of insulin. Additionally, the liver can potentially turn excessive protein into glucose. If patients are not losing weight or are not seeing significant ketone generation, check that their carbohydrate intake is low, they are not snacking between meals, and they are not consuming excessive fat. If none of those are issues, then ask them to calculate protein intake to see if they are over- or under-eating protein.
Some patients may need to temporarily reduce their protein intake to about 1.0 g/kg of lean mass if they are struggling to get into ketosis. However, we still need to ensure they have adequate protein intake long term to avoid sarcopenia and to promote building lean body mass. Therefore, approach protein reduction as a temporary trial rather than a long-term change.
Learn more about protein recommendations in our guide, Protein on a low carb or keto diet.
2. Allergy to nuts
Many patients worry they cannot do LCHF or keto successfully if they cannot eat nuts. Many low-carb recipes — especially ones for keto bread, pancakes or other replacement high carb products — rely on nut flours, especially almond flour.
Nuts may be useful, especially at first when adapting to this new way of eating, but they are not necessary for success.
Coconut flour can be used instead because coconuts are not part of the nut family. Recipes will need to be adjusted, as coconut flour requires more liquid. (Note: Lupin flour should not be used, as there is a risk for cross-allergy with nuts.)
Even better, encourage your patient to focus on whole foods without nut products as they are not necessary for a healthy low-carb diet.
3. Female patients with cycle-related weight gain
Weight gain around the menstrual period is common for women, usually due to increasing water retention.
However, cravings and compliance with the diet can also be difficult for some women, especially at the premenstrual time of the cycle. Potential ways to deal with cravings include:
- Recommend reducing or eliminating sugar substitutes during other times of the month to reduce the taste for sweet foods.
- Alternatively, if sweeteners are generally not used but the patient craves sugary foods during the premenstrual phase, suggest using non-calorie sweeteners during this time only.
- Eating pork rinds or cheese can remedy cravings without spiking insulin or glucose.
- Low-carb substitutes for high-carb foods — such as Fathead pizza, keto pancakes, keto brownies — can satisfy a craving without the loss of dietary control.
Help your patient understand that this is a common occurrence, and if it happens to them they should prepare for it, instead of getting caught off guard every month.
4. Ketosis cannot be achieved or maintained
This is not uncommon in the early stages of a low-carb diet. It usually takes time for the body to enter and stay in ketosis, even when the diet is very low in carbs. This depends on many factors, including the severity of baseline insulin resistance.
Verify why patients want to be in ketosis, and if not being consistently in ketosis is causing them stress. They may think they need to be in ketosis in order to lose weight or reverse their diabetes, which is not true.
Asking your patients to keep a detailed food journal or use a macro-calculating app might reveal hidden carbs.
If patients are using urine strips to verify their ketone levels, this might not be reliable after a few weeks of ketosis, when the kidneys begin reabsorbing ketones more efficiently. Patients may want to invest in a blood ketone meter if results will provide information and motivation to stay on the diet. Learn more in our guide to testing ketones.
If a patient clearly benefits from being in ketosis and there isn’t an obvious dietary fix, you can also consider time-restricted eating or intermittent fasting to help maintain ketosis.
5. Patient is vegetarian
A healthy low-carb vegetarian diet is challenging but completely possible. The main concerns are eating too many carbs and not enough protein. Yet with proper attention to eating legumes and tofu, non-starchy vegetables, dairy and eggs, you can reassure them they can do it. However, since vegetarians may be more likely to over-do carbs compared to non-vegetarians, they may need to count carb grams, at least in the beginning, to ensure they are staying below their carb goals.
Read more in our evidence-based guide, How to follow a healthy vegetarian keto diet.
A healthy, nutritious LCHF vegan diet is even more challenging but also doable with proper attention and supplementation. Again, make sure they are not over-consuming carbohydrates and that they are getting adequate protein for long-term health.
You can read more details in our evidence-based guide, How to eat low carb as a vegan.
6. Patient is fat phobic
After more than 40 years of low-fat messages, some patients have a strong distaste or even outright fear of fat. Success on the LCHF diet, however, requires that when they decrease carb consumption they must increase fat consumption. Otherwise, their bodies may assume they are starving and lower their basal metabolism rate to conserve energy.
Having a fat bomb for dessert is a delicious way to increase fat consumption. Other suggestions are:
- Add avocado and olive oil to everything
- Add 1-2 tbsp of fat, such as butter, to each meal
- Add cream, MCT oil or coconut oil to coffee or tea in between meals
- Take a tablespoon of whipping cream, MCT oil, or coconut oil on its own when feeling lethargic
Note: Warn patients to be careful with MCT oil, as taking too much too fast can cause diarrhea. This oil is almost tasteless and can easily be added to coffee or tea. We suggest starting with a teaspoon or less and increasing gradually.
7. Patient’s ketone levels are high
Some people have a higher threshold before their bodies halt the production of ketones. While optimal ketosis is anywhere from 0.5 to 3.0 mmol/L some patients will register levels between 4.5 and 6 mmol/L. This seems high, but it is still far from the ketoacidosis zone of 10 mmol/L and above.
Higher ketone levels do not necessarily mean more weight loss is happening or that the body is using ketones properly. They can increase with fasting and exercise, or may simply “run high” without a clear explanation.
This can also can occur secondary to your patient eating large amounts of coconut oil and MCT oil. After absorption into bloodstream, MCTs go straight to the liver, where they can be converted into ketones. If this is the case, the patient should cut back on added fat, as this may be preventing the body from burning its own fat stores.
Check that your patient is eating enough protein at each meal, especially if vegan or vegetarian. A lack of protein may increase the production of ketone bodies as a form of starvation ketosis.
Family, medical, or social supports
- Unsupportive health care professionals
- Unsupportive spouse or family
- No time to prepare two meals for non-LCHF family
- Travel or life demands restaurant meals
- Low income
1. Unsupportive health care professionals
Since LCHF or ketogenic eating is not yet uniformly recognized as the standard of care for weight loss or diabetes reversal, patients may hear conflicting or unsupportive messages from members of their health care team.
This can cause considerable confusion or even hesitation to continue the diet.
We encourage pointing them to evidence-based resources like our science of low carb and keto guide. It is important to help them see the difference between objective science and the potentially misguided low-fat teachings of the past decades.
Make sure to highlight any health improvements, such as lab results, body weight, waist circumference, or even the freedom of no longer having fluctuations in energy and hunger during the day. If patients are still concerned about the inconsistent messages, you can always suggest a self-experiment where they try various diets for 30-60 days, such as low-fat calorie restriction, DASH, Mediterranean, et cetera. They can track how they feel, their weight, and recheck lab markers after each experiment.
That may help them find the right dietary choice for them, at least in the short term. Then you can devise a plan for continued long-term follow up to ensure health markers continue to improve.
It is important for your patients to know that they are not “on their own” but rather are part of a healthcare team with you. That way, if they hear from another healthcare professional that they are “killing themselves with all that fat,” or they “need whole grains for their health,” they will feel confident that they are being adequately monitored, and you will know right away if any negative health consequences occur.
2. Unsupportive spouse or family
Lack of support at home is one of the most common reasons for lack of success with a LCHF lifestyle.
We suggest some of the following actions for your patients:
- Ask their family members to allow them the space to try it without criticism for 30 days. People tend to become more willing to commit to a time-limited experiment. Then, if they start to see results, they will likely be more supportive long-term. It may seem like overkill, but having a written contract helps some people understand the importance of the situation.
- Consider not discussing their diet and fasting schedule with unsupportive friends and relatives. If asked, they can simply say they are focusing on eating plenty of vegetables and protein, and cutting out sugars.
- Join an online community such as the many on Facebook for ongoing support.
- Ask children or partners to only eat processed, high-carb food outside of the home, or at least not in their presence. Some people find it helpful to say they have a “food allergy” to grains and sugars.
We suggest more frequent follow-ups with such patients, as they are at higher risk of giving up due to pressure from their families and friends. Have your nurse or support staff give extra initial encouragement.
3. No time to prepare two meals for non-LCHF family
Many patients simply don’t have the time to make a low-carb meal for themselves and higher-carb meals for the rest of the family. We suggest avoiding one-dish starch-based recipes like lasagna, pasta dishes or shepherd’s pie. Instead, instruct them to keep meals simple. Prepare meat or fish with green vegetables and olive oil and add a simple starchy side dish like potatoes, rice or pasta for those who want it. Having a “deconstructed” meal like this makes it much easier to keep everyone happy. The other trick is to make good use of leftovers to prevent cooking every night.
It is also important to point out that all members of the family, especially children and teens, can benefit from eating less sugar and refined carbohydrates. There are dozens of delicious recipes on Dietdoctor.com that are family-friendly and very popular. Some of the most popular are the starch substitutes like keto bread, zucchini noodles, and keto pizza.
4. Travel or life demands restaurant meals
We should encourage freshly-prepared, home-cooked meals, but in reality that it isn’t always possible. A heavy travel schedule, long work days or family demands may lead to grabbing food on the go from restaurants or fast food spots.
The good news is that it’s possible to eat low carb in almost any type of restaurant. Some places may not have the same selection of quality meat or unprocessed cooking oils, but it doesn’t mean your patients have to go off plan.
Encourage your patients to order burgers without ketchup, bun or fries. Most places will provide a lettuce wrap or bowl. A quarter chicken with a side salad (skip the croutons) is another easy option, as are breakfast sandwiches without the bun — just the eggs, ham and cheese, eaten with a knife and fork.
In sit-down restaurants, it’s usually possible to have a steak, chicken leg, or filet of salmon. Simply skip the starchy sides and ask for extra green vegetables with olive oil.
If a basket of bread is placed on the table, keep the butter, but ask the waiter to remove the bread.
Traveling is also a perfect time to encourage your patients to try intermittent fasting.
5. Low income
For some people, a low income or small food budget may seem like a barrier to healthy low-carb eating. While there are many fancy online recipes with expensive ingredients like grass-fed beef, almond flour, erythritol, MCT oil, and others, it is not necessary to bake or cook anything elaborate. Here are some simple tips for your patients:
- Try intermittent fasting to cut down on total meals and meal prep.
- Breakfast can be a hot beverage, like coffee or tea with cream or butter.
- Focus on restricting carbs more than seeking the highest quality and most expensive ingredients (For instance, 2 conventional burger patties from a fast food place is still better than a grass-fed burger with chips, fries and a soda).
- Organ meats and the fattiest cuts of meat are often the cheapest ones. Suggest that patients buy what is on special each week at the grocery store, and explore new ways to cook these cuts.
See more in our guide, Low-carb and keto on a budget.
Gastroenterology Research and Practice 2017: Impact of time-restricted feeding and dawn-to-sunset fasting on circadian rhythm, obesity, metabolic syndrome, and nonalcoholic fatty liver disease [overview article; ungraded] ↩
This is based on findings that uric acid levels may rise initially on a low-carb diet. However, clinical experience shows that this is accompanied by a very small increased risk of gout, if at all. [weak evidence] ↩
Sugar is likely worse than other carbohydrates because of the high concentration of fructose, which raises uric acid. This study showed lowering the glycemic index of carbohydrates improved uric acid levels:Arthritis and Rheumatology 2017: Effects of lowering glycemic index of dietary carbohydrate on plasma uric acid: The OmniCarb Randomized Clinical Trial[randomized trial; moderate evidence] ↩
Journal of Clinical and Diagnostic Research 2013: Correlation of the serum insulin and the serum uric acid levels with the glycated haemoglobin levels in the patients of type 2 diabetes mellitus [observational study, weak evidence] ↩
This study showed most types of alcohol, even in moderate amounts, increased risk of gout. However, it is likely that none of the participants were on a low-carb diet:American Journal or Medicine 2015: Alcohol quantity and type on risk of recurrent gout attacks: An internet-based case-crossover study [weak evidence] ↩
International Journal of Obesity and Related Metabolic Disorders 1988: Gallbladder motility and gallstone formation in obese patients following very low calorie diets. Use it (fat) to lose it (well) [non-randomized trial; weak evidence] ↩
Kidney stones have been reported in children with epilepsy who use special, highly-restrictive versions of ketogenic diets, but supplementing with potassium citrate may reduce the risk of kidney stones five-fold:
Importantly, this doesn’t seem to be a risk on a less-restrictive diet based on whole foods. ↩
Journal of Genetic Syndromes and Gene Therapy 2011: Neuro-Genetics of reward deficiency syndrome (RDS) as the root cause of “Addiction Transfer”: A new phenomenon common after bariatric surgery [overview article; ungraded] ↩
Cardiovascular Diabetology 2018: Cardiovascular disease risk factor responses to a type 2 diabetes care model including nutritional ketosis induced by sustained carbohydrate restriction at 1 year: an open label, non-randomized, controlled study [non-controlled study; weak evidence] ↩