What to do about a lack of energy on low carb?


Is a low-carb diet appropriate for someone who has had gastric-bypass surgery? Can you lose weight on low carb while taking insulin? And what to do about a lack of energy on low carb?

Get the answers in this week’s Q&A with Dr. Andreas Eenfeldt:

Low carb and gastric-bypass surgery?

Is a low-carb diet suitable for someone who has had a gastric bypass surgery?


Yes, very much so. As it’s hard to eat more than small amounts after surgery, it’s a great idea to avoid nutrient-poor carbohydrates (like bread). It’s also a great way to stop and reverse the regain of weight that often happens a year or so after surgery-induced weight loss.

Here’ are several happy people who have tried it:

Andreas Eenfeldt

Question about insulin

Can you lose weight on this type of diet while taking insulin?


Yes. However be aware you’ll need LESS insulin on a low-carb diet. Be very careful when starting out so that you don’t overdose your insulin, resulting in hypoglycaemia.

Reducing insulin doses by adapting them to your lower needs on low carb will also help with weight loss.

Starting low carb with diabetes medications, e.g. insulin

Andreas Eenfeldt


Lack of energy

Hello Dr. Andreas,

I have been following the keto diet since January and I am very pleased with the diet overall. I have lost 20 lbs (9 kg) and it’s been fairly easy to follow the plan. I have had some problem with leg cramps, but the biggest issue I have had is a lack of stamina when I am active. I love to go on hikes and bike rides and since on this diet I don’t feel I have the same endurance I had in the past. Any thing I can do, or eat that may help before I take a hike?


Yes, get some extra salt and fluid. Like a cup or two of bouillon, or a few grams of salt diluted in water. This may help to increase energy generally on low carb, if so the effect should be noticed within 15-30 minutes.

If that does not help enough, you may benefit from a moderate amount of carbs before those physical activities, like a small amount of rice or a few potatoes with a meal.

Learn more about how to increase physical performance on low carb

Andreas Eenfeldt


Low Carb for Beginners

More Questions and Answers

Low-Carb Q&A


More about low carb and weight loss


  1. Santi
    This isn't directly related to the article, however since it's the freshest news I was hoping I would get the fastest response.
    I have been on a keto diet for just over 2 weeks and have had fantastic results.
    I have paired it with intermittent fasting and maybe this is due to being 19 years old, but it's actually amazing how well this works.
    However, my main concern is that I wanted to maintain this for 1 month as a way to lose body fat and start toning.
    What is a safe way to start eating carbs again without gaining weight dangerously? (I understand I should gain around 3 kilos of water weight).
    Kind Regards.
  2. Debra Brooks
    Add carbs slowly and systematically. Like, 10 added a day for a week. If you keep losing weight then you add more until you stop losing weight. If you get to the point you start gaining weight, you are adding too many carbs and need to cut back. Weigh daily until you reach your goal. If you start gaining weight and need to cut back on carbs, it will take your body days before you start losing again. People gain weight after this diet because they think they can eat like they did prior to changing their food intact. For long term consistent weight loss and maintenance, low carb is not a diet. It is a way of life. When you cheat and eat too many carbs even a couple times, it takes your body a few days again to get back in ketoacidosis and weight lose. Im not sure why you expect to gain water weight. Your water intake should not cause weight gain if you are active enough. Look up info on being over hydrated. It may help you. Good luck to you

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