Food policy

The Diet Doctor food policy

There are many thoughts and ideas about what foods are and aren’t part of a healthy low-carb or keto diet, and that can sometimes be confusing, to say the least. With this food policy we aim to make transparent where we stand on the matter and what foods you can expect from our low-carb and keto recipes.

Our goal, to empower people everywhere to revolutionize their health, humbles us to the fact that all individuals are different and have different needs at different times. We hope you will find this policy helpful when you embark on the journey of finding out what foods work best for you.

 


Different levels of low carb

Here’s how we define different levels of low carb at Diet Doctor:

  • Ketogenic low carb <20 gram net carbs per day.1 This is a ketogenic diet (if protein intake is moderate). This level is defined as below 4 energy percent (E%) carbs in our recipes.2 We also keep the protein level low or moderate (excess protein is converted to carbohydrates in the body).34 In our ketogenic recipes the amount of carbs per serving is shown in green balls.
  • Moderate low carb 20-50 net grams per day. This level is defined as between 4-10 E% carbs in our recipes and the amount of carbs per serving is shown in yellow balls.
  • Liberal low carb 50-100 net grams per day. This means 10-20 E% carbs in our recipes and the amount of carbs per serving is shown in orange balls.

 



Low-Carb Vegetables

Carbohydrates (carbs)

We aim to provide recipes with 0–20 percent of the total energy intake coming mostly from unprocessed real food carb sources (e.g. vegetables).

Carbs are not essential to the human body but if they come from unprocessed food, they contribute nutrients and fiber.56 They also give you the possibility to vary how you eat and add texture and color to your plate.

We show net carbs (total carbs with fiber subtracted) because in most people the fiber doesn’t cause a rise in blood glucose or insulin.7

Visual guide: Low-carb vegetables – the best and worst

 
 


Protein

We recommend meat, poultry, fish, seafood, eggs and/or dairy as sources of protein, preferably as unprocessed as possible.8

Protein is essential to the human body but an excess intake can lead to some of the protein turning into glucose, which may raise insulin levels and reduce ketosis.9 This is why we slightly limit protein in our keto recipes but not otherwise.10

Learn more about our policy on protein

Check out our guide about protein

 


Low-Carb Fats & Sauces

Fat

Some dietary fat is essential to the human body.11 We primarily recommend fat that’s part of natural foods such as fatty cuts of meat, eggs and avocados over added oils and butter.12

Minimally processed added fats, such as butter, olive oil and coconut oil can be used in amounts needed to provide satiety.13 However, they should still be seen as a modest part of one’s diet and not the main component due to their relative lack of essential nutrients.

Vegetable and seed oils (except olive or coconut oil) are often high in omega-6 fats and, therefore, are not something we recommend. Examples of these non-recommended vegetable and seed oils are soybean oil, corn oil and sunflower oil. In large quantities omega-6 fats might potentially increase inflammation.14 These fats may also be less tolerant to heating, potentially forming harmful substances when used for frying.15 Processed fats such as margarine are not used on our site.


 
 


Higher-carb ingredients

We see real foods high in carbs, like potatoes and rice, as something that can be a part of a healthy diet, in small to moderate amounts, for most people (especially if they are insulin sensitive).

However, such foods are high in carbs, reduce the effects of a low-carb diet, and can be a problem for insulin-resistant people.16 Therefore, we have chosen to not include potatoes, rice and other starches in our meal plans or recipes.

Herbs, like buckwheat and quinoa, are not something we recommend eating large amounts of, but are theoretically allowed in quantities that keep the recipes within our set limits for carbs. As a general rule, we don’t use them in our keto recipes.

 



Low-Carb Fruits

Fruits and berries

We see fruits and berries as nature’s candy and something that can be a part of a healthy diet, in small to moderate amounts, for most people.17 However, fruit contains a large proportion of calories from sugar. Thus, people with insulin resistance, e.g. people with type 2 diabetes, may want to mostly avoid fruit.18

We aim to clearly mark recipes with a significant amount of sugar in them as moderate or liberal. This is to make it simple for people sensitive to sugar, such as people with diabetes, to take that into consideration.19

As a general rule, we don’t have any fruit in our keto recipes. Berries are usually a lower-carb option and are used in recipes as long as they stay within our set limits for carbs.

Additionally, although we occasionally use very small amounts of citrus juice in some of our recipes, we ensure that they fall within our established carb limits.

Visual guide: Low-carb fruits and berries – the best and worst

 
 


Low-carb sweeteners

Sweeteners

We recommend minimizing the use of non-caloric sweeteners due to the potential for addiction, maintaining a preference for sweet tastes or stimulating over-consumption.20 Some people can also experience gastrointestinal problems when consuming.21

Certain sweeteners that we deem potentially less harmful, such as erythritol and stevia, may be used in small amounts in our low-carb and keto dessert recipes.22

Visual guide: Low-carb sweeteners – the best and worst

 
 


Sugar

We don’t see a need to use pure regular sugar, brown sugar, honey or agave in our recipes because they don’t provide anything necessary for a healthy diet.

Sugar raises blood glucose which causes insulin release, and it also has other potentially negative effects (see guide below).23

Learn more about sugar and its effects on your health

 


Gluten

We don’t use ingredients containing gluten knowingly because it can cause problems for people sensitive to it, even in small amounts.24

We can’t guarantee that some ingredients used in our recipes (ground psyllium husk, oat fiber and protein powder etc.) haven’t been contaminated in production.25

Learn more about gluten and wheat

 


Gluten-free grains

Gluten-free grains, such as oats, are not something we recommend eating a lot of due to their high carb content.26

We do think that in small to moderate amounts, they can be part of a healthy diet for insulin-sensitive people. That’s why small amounts of gluten-free grains are allowed in our moderate and liberal low-carb recipes as long as they stay within our set limits for carbs. As a general rule, we don’t use them in our keto recipes.

However, some of our keto and low-carb recipes do contain oat fiber, which does not raise blood sugar and insulin because it is not digested and absorbed by your body.27  


Dairy products

We use full-fat dairy products such as butter, heavy whipping cream, yogurt and cheese in our recipes unless they are marked as dairy-free.28 Full-fat dairy products have a high protein and/or fat content, which can increase satiety.29

Learn more about dairy on a low-carb diet

 


Low-Carb Nuts

Nuts and seeds

Nuts and seeds are used in our recipes, both in their natural form and as flours. They add texture and flavor and can be used as a handy snack.30

The carb content between different nuts and seeds varies quite a lot and if used in a recipe it must stay within our set limits for carbs.

Visual guide: Low-carb nuts – the best and worst

 


Meat

A healthy low-carb diet can contain meat, but it’s also very possible to eat a meat-free low-carb diet.

Regarding eating meat or not, we are neutral.

The Diet Doctor policy on eating meat

Guide to red meat – is it healthy?

How to follow a healthy vegetarian keto diet


 


Legumes

Some legumes (sometimes referred to as grain legumes or pulses) – such as beans, lentils, peas and peanuts – are fairly high in carbs but are allowed in our recipes as long as the recipe itself stays within our set limits for carbs.

Legumes have varying amounts of resistant starch, which may have a lowering effect on blood sugar for some people, potentially mitigating the effects of the other carbohydrates somewhat.31

Learn more about resistant starch

 


Soy

Products made from soy, like tofu, can provide a good source of protein for vegetarians and vegans who follow a low-carb diet. However, concerns have been raised about the health effects of soy isoflavones based on animal and test-tube studies.32 By contrast, the research on soy in humans is mainly positive regarding safety and disease risk.33

Although soy doesn’t seem to cause problems for people with normal thyroid function, there’s been conflicting evidence in those with subclinical hypothyroidism (also known as mild thyroid failure).34

Soy isoflavones may interfere with thyroid hormone absorption when iodine intake isn’t sufficient.35 Therefore, it may be important to get enough iodine when consuming soy regularly, especially for those with hypothyroidism. Good sources of iodine include iodized salt, seaweed, seafood, and yogurt.

At this time, some concerns remain about soy consumption in people with thyroid problems, as well as the long-term health effects of consuming ultra-processed products like soy protein powders and supplements.36 Choosing whole and/or fermented soy (tempeh, natto) might be a better option than other soy products.

Some people have raised concerns that many soy products in the US may contain residues of glyphosate (Roundup), a controversial herbicide used on soy and other crops that requires further study.37 Fortunately, organic and non-GMO soy products contain no glyphosate.38 If you want to eat soy while avoiding glyphosate, choose tofu, tempeh, and natto labeled “non-GMO.”

For people who want to avoid animal products, the benefits of soy seem to greatly outweigh the risks. Although the potential risk to thyroid function appears very small, those who consume soy on a regular basis may want to consider having their thyroid function monitored periodically and including iodine food sources in their diet.

Guide: How to follow a healthy vegetarian keto diet

 


Chocolate

Dark chocolate with ≥70% cocoa solids (preferably ≥85%) and sugar-free chocolate may be used in our dessert recipes if they stay within our set limits for carbs. It’s only allowed in desserts and intended for occasional consumption, not in breakfast or snack recipes or in recipes that can be considered everyday foods.

However, unsweetened cocoa powder may be added to coffee or consumed as hot cocoa on a more frequent basis, as it contains a minimal amount of net carbs.39

 


  1. Net carbs = digestible carbs, i.e. total carbs minus fiber.

  2. The limit of four percent energy means that you’ll stay below a maximum 20 grams of carbs on a 2,000-calorie diet, even if you only choose our most carb-rich keto recipes.

    In most cases you’ll end up with far fewer carbs than that, as some of the keto recipes you use are likely to have significantly less than the maximum amount of carbs.

  3. As excess protein can reduce ketosis, our keto recipes are also limited in protein. Our rule is that for keto recipes with 4 energy percent carbs we accept a maximum of 25 energy percent protein. For lower carb levels we accept slightly more protein:

    • 3 % carbs = max 27 % protein
    • 2 % carbs = max 29 % protein
    • 1 % carbs = max 31 % protein
    • 0 % carbs = max 33 % protein

     
    If there’s too much protein in a recipe to classify it as keto low carb, we instead classify it as moderate low carb.

    Note that we use percent protein in our recipes for simplicity, but what really matters most is the absolute amount of protein you eat per day. If you eat very little, you may stay in ketosis even with a higher percentage protein. In this case, your protein intake probably shouldn’t exceed 1.7 grams per kg of body weight.

    Learn more in our full protein guide

  4. The process of converting excess protein to glucose is called gluconeogenesis (literally “making new glucose”). During digestion, protein is broken down into individual amino acids, which your body can use to make glucose.

    International Journal for Vitamin and Nutrition Research 2011: Protein turnover, ureagenesis and gluconeogenesis [overview article]

  5. US Food and Nutrition Board’s 2005 textbook “Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids”, stated that:

    “The lower limit of dietary carbohydrate compatible with life apparently is zero, provided that adequate amounts of protein and fat are consumed.”

    Learn more: Food for thought: Does the brain need carbs?

  6. Advances in Nutrition 2012: Health benefits of fruits and vegetables [overview article]

  7. Although some low-carb experts disagree, it’s generally accepted that humans lack the enzymes needed to break down fiber and absorb it into the bloodstream. Therefore, the fiber portion of carbs does not raise blood sugar and insulin levels.

    Nutrients 2010: Effects of dietary fiber and its components on metabolic health [overview article]

  8. In addition to containing fewer carbs than most plant sources of protein, animal protein is considered higher quality because it contains all 9 essential amino acids – the ones your body can’t make on its own – in optimal amounts.

    Journal of Cachexia, Sarcopenia and Muscle 2017: Dietary protein content for an optimal diet: a clinical view [overview article]

    Scientific Reports 2016: Essential amino acids: master regulators of nutrition and environmental footprint? [overview article]

  9. Gluconeogenesis is a demand-driven process that occurs whenever glucose is needed. For instance, when someone follows a carb-free diet, gluconeogenesis will provide glucose for the few parts of the body that can’t use ketones: red blood cells and portions of the kidney and brain.

    American Journal of Clinical Nutrition 2009: Gluconeogenesis and energy expenditure after a high-protein, carbohydrate-free diet [moderate evidence]

    Very high protein intake on a keto or low-carb diet may also lead to gluconeogenesis.

    Diabetologia 2000: Effect of long-term dietary protein intake on glucose metabolism in humans [moderate evidence]

    However, reports from physicians who recommend a higher-protein, low-carb way of eating suggest that blood sugar response to this approach can vary quite a bit from person to person.

  10. Our rule is that for keto recipes with 4 energy percent carbs we accept a maximum of 25 energy percent protein. For lower carb levels we accept slightly more protein:

    • 3 % carbs = max 27 % protein
    • 2 % carbs = max 29 % protein
    • 1 % carbs = max 31 % protein
    • 0 % carbs = max 33 % protein

     
    If there’s too much protein in a recipe to classify it as keto low carb, we instead classify it as moderate low carb.

  11. While we recommend consuming adequate amounts of good-quality fat, technically only alpha-linolenic (omega-3) and linoleic (omega-6) fatty acids are essential, meaning they must be consumed in the diet because your body can’t make them.

    Journal of Dietary Supplements 2009: The essentials of essential fatty acids [overview article]

  12. The reason is that these foods have significantly higher levels of essential nutrients, compared to added fats.

  13. Many natural fat sources are high in saturated fatty acids. This should no be longer considered harmful, as modern science has shown saturated fat to be more or less neutral from a health perspective.

    A user guide to saturated fat

    Annals of Nutrition & Metabolism 2009: Dietary fat and coronary heart disease: summary of evidence from prospective cohort and randomised controlled trials [strong evidence]

    Open Heart 2015: Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis [strong evidence]

  14. However, results from controlled trials investigating a relationship between omega-6 fatty acids and inflammation have been mixed. Further research in this area is needed.

    Prostaglandins, Leukotrienes & Essential Fatty Acids 2018: Omega-6 fatty acids and inflammation [overview article]

  15. Indian Journal of Clinical Biochemistry 2000: Lipid peroxidation in culinary oils subjected to thermal stress [moderate evidence]

  16. Nutrition & Metabolism 2017: Hepatic, adipocyte, enteric and pancreatic hormones: response to dietary macronutrient composition and relationship with metabolism [moderate evidence]

  17. What fruits and vegetables looked like before

  18. People with type 2 diabetes often do better on a very low-carb diet:

    Diabetes Research and Clinical Practice 2018: Effect of dietary carbohydrate restriction on glycemic control in adults with diabetes: A systematic review and meta-analysis [strong evidence]

  19. Studies have found that people with diabetes achieve better blood sugar and insulin control when consuming keto diets that contain minimal to no fruit vs. diets that contain moderate amounts of fruit.

    Nutrition & Metabolism 2008: The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus [moderate evidence]

    Nutrition & Diabetes 2017: Twelve-month outcomes of a randomized trial of a moderate-carbohydrate versus very low-carbohydrate diet in overweight adults with type 2 diabetes mellitus or prediabetes [moderate evidence]

    Journal of Medical Internet Research 2017: An online intervention comparing a very low-carbohydrate ketogenic diet and lifestyle recommendations versus a plate method diet in overweight individuals with type 2 diabetes: a randomized controlled trial [moderate evidence]

  20. At this time, research remains inconclusive regarding the effects of sweeteners on appetite, cravings, and overeating:

    Nutrition Journal 2017: Health outcomes of non-nutritive sweeteners: analysis of the research landscape [strong evidence]

    However, many people have reported experiencing these effects when consuming artificial sweeteners.

    Nutrients 2018: The impact of caloric and non-caloric sweeteners on food intake and brain responses to food: a randomized crossover controlled trial in healthy humans [moderate evidence]

    The American Journal of Clinical Nutrition 2015: Effects on weight loss in adults of replacing diet beverages with water during a hypoenergetic diet: a randomized, 24-wk clinical trial [moderate evidence]

  21. This includes potential changes to the gut microbiome:

    Advances in Nutrition 2019: Effects of sweeteners on the gut microbiota: a review of experimental studies and clinical trials [strong evidence]

  22. Stevia and erythritol have minimal, if any, effects on blood sugar and insulin levels. They are generally considered safe and well tolerated when used in small amounts on an occasional basis.

    American Journal of Physiology, Endocrinology & Metabolism 2016: Gut hormone secretion, gastric emptying, and glycemic responses to erythritol and xylitol in lean and obese subjects [moderate evidence]

    European Journal of Clinical Nutrition 2015: Gastrointestinal tolerance of erythritol-containing beverage in young children: a double-blind, randomised controlled trial [moderate evidence]

    Current Pharmaceutical Design 2017: A review on the pharmacology and toxicology of steviol glycosides extracted from Stevia rebaudiana [overview article]

    Clinical Therapeutics 2003: Efficacy and tolerability of oral stevioside in patients with mild essential hypertension: a two-year, randomized, placebo-controlled study [moderate evidence]

  23. Keep in mind that sugar is sugar. “Natural” sugars like honey have been shown to raise blood glucose and insulin levels as much as white sugar and high-fructose corn syrup:

    Journal of Nutrition 2015: Consumption of honey, sucrose, and high-fructose corn syrup produces similar metabolic effects in glucose-tolerant and -intolerant individuals [weak evidence]

  24. This may be true for both for people with celiac disease and those with non-celiac gluten sensitivity.

    Nutrients 2016: Evidence for the presence of non-celiac gluten sensitivity in patients with functional gastrointestinal symptoms: results from a multicenter randomized double-blind placebo-controlled gluten challenge [moderate evidence]

    Nutrients 2019: Exposure to different amounts of dietary gluten in patients with non-celiac gluten sensitivity (NCGS): an exploratory study [weak evidence]

  25. If you have celiac disease or are gluten sensitive, you may want to purchase ingredients that are certified or verified gluten-free.

  26. Furthermore, some inherently gluten-free grains, seeds, and flours (e.g. oats, millet flour, soy flour) not labeled gluten-free might sometimes be contaminated with gluten while being harvested, transported, and/or processed.

    This potential risk of contamination could be a health concern for gluten-sensitive people.

    Journal of the American Dietetic Association 2010: Gluten contamination of grains, seeds, and flours in the United States: a pilot study [moderate evidence]

  27. Humans lack the enzymes needed to break down fiber and absorb it into the bloodstream. Therefore, the fiber portion of carbs does not raise blood sugar and insulin levels.

    Nutrients 2010: Effects of dietary fiber and its components on metabolic health [overview article]

  28. The fear of saturated fats, like those in dairy, appears to have been completely misguided:

    Nutrition Journal 2017: The effect of replacing saturated fat with mostly n-6 polyunsaturated fat on coronary heart disease: a meta-analysis of randomised controlled trials [strong evidence] (analysis)

  29. Studies suggest that consuming dairy products may help people achieve and maintain a healthy weight by promoting satiety and reducing overall food intake:

    Clinical Nutrition 2017: Dairy products, satiety and food intake: a meta-analysis of clinical trials [strong evidence]

    Nutrients 2016: Regular-fat dairy and human health: a synopsis of symposia presented in Europe and North America (2014-2015) [overview article]

  30. Nuts also contain several micronutrients and may have generally positive health effects:

    Nutrients 2017: Nuts and human health outcomes: a systematic review [strong evidence]

  31. Resistant starch “resists” digestion in the intestinal tract and instead passes directly into the colon, where bacteria ferment it into short-chain fatty acids that may potentially improve blood glucose regulation.

    Note, however, that the studies below used large amounts of resistant starch (10 or 30 grams per day). It may be unpractical to get as much resistant starch from legumes, that usually contain about 1-4 grams of resistant starch per 100 grams.

    Nutrition Journal 2017: Resistant starch lowers postprandial glucose and leptin in overweight adults consuming a moderate-to-high-fat diet: a randomized-controlled trial [moderate evidence]

    Complementary Therapies in Medicine 2015: Is there any place for resistant starch, as alimentary prebiotic, for patients with type 2 diabetes? [moderate evidence]

    European Journal of Nutrition 2016: Effects of total fibre or resistant starch-rich diets within lifestyle intervention in obese prediabetic adults [moderate evidence]

  32. Isoflavones are a type of phytoestrogen (plant compounds that have a structure similar to estrogen) found in soy and other legumes.

  33. This is true for observational studies spanning many years as well as shorter but much higher-quality clinical trials:

    Advances in Nutrition 2018: Associations between phytoestrogens, glucose homeostasis, and risk of diabetes in women: a systematic review and meta-analysis [systematic review of randomized trials; strong evidence]

    PloS One 2013: Soy, red clover, and isoflavones and breast cancer: a systematic review [systematic review of randomized trials; strong evidence]

    Gynecological Endocrinology 2013: Endometrial, breast and liver safety of soy isoflavones plus Lactobacillus sporogenes in post-menopausal women [randomized trial; moderate evidence]

    Nutrients 2018: Soy, soy foods, and their role in vegetarian diets [overview article; ungraded]

  34. Scientific Reports 2019: Systematic review and meta-analysis on the effect of soy on thyroid function [strong evidence]

    EFSA Journal 2015: Risk assessment for peri- and post-menopausal women taking food supplements containing isolated isoflavones [systematic review of clinical studies; strong evidence]

    The Journal of Clinical Endocrinology & Metabolism 2011: The effect of soy phytoestrogen supplementation on thyroid status and cardiovascular risk markers in patients with subclinical hypothyroidism: a randomized, double-blind, crossover study [moderate evidence]

    Journal of the Endocrine Society 2017: Soy protein improves cardiovascular risk in subclinical hypothyroidism: a randomized double-blinded crossover study [moderate evidence]

    Frontiers in Endocrinology 2017: The effect of phytoestrogen on thyroid in subclinical hypothyroidism: randomized, double blind, crossover study [moderate evidence]

  35. Thyroid 2006: Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: a review of the relevant literature [overview article; ungraded]

  36. Alternative Therapies in Health & Medicine 2014: Soy foods and supplementation: a review of commonly perceived health benefits and risks [overview article; ungraded]

  37. Archives of Toxicology 2017: Glyphosate toxicity and carcinogenicity: a review of the scientific basis of the European Union assessment and its differences with IARC [expert review; ungraded]

  38. After testing 31 batches of soybeans, researchers found that unlike genetically-modified soybeans, conventional and organic soybeans contained no glyphosate:

    Food Chemistry 2014: Compositional differences in soybeans on the market: Glyphosate accumulates in Roundup Ready GM soybeans [mechanistic study; ungraded]

  39. Some studies suggest it might even have benefits for heart and gut health:

    Journal of Nutrition 2016: Cocoa flavanol intake and biomarkers for cardiometabolic health: a systematic review and meta-analysis of randomized controlled trials [strong evidence]

    American Journal of Clinical Nutrition 2011: Prebiotic evaluation of cocoa-derived flavanols in healthy humans by using a randomized, controlled, double-blind, crossover intervention study [moderate evidence]