How to transition from weight loss to maintenance mode?

Ask Dr. Jason Fung

How should you transition from weight loss to maintenance mode? Are there guidelines for fasting for health benefits and not weight loss? Is it true that we can never lose fat cells, but only shrink them? And can fasting cause high blood pressure?

It’s time for this week’s Q&A about intermittent fasting and low carb with Dr. Jason Fung:

Life-long maintenance

I do not see too much information about the transition from weight loss to life-long maintenance. It is possible I am just missing it. How do we know when to maintain and what is the recommended plan to do so? Some LCHF plans, like Atkins, give a path to maintenance. What are your thoughts on life-long maintenance?

Thank you,

There is no specific transition. Weight loss will generally plateau at a specific weight. Sometimes that weight is too high, and that means changing the dietary regimen. The principles all remain the same. Eat if you are hungry. Do not eat if you are not. If you want to lose more weight, increase fasting periods. Eat real foods. etc.

Dr. Jason Fung

Intermittent fasting for health benefits but NOT weight loss?

Hi there,

I have been following a ketogenic diet for 14 weeks and really enjoy it. I’ve lost about 15 lbs (7 kg) in that time and my BMI is now around 20. My main reason for starting the keto diet was for the health benefits (I have moderate ME/CFS) and I’ve seen an amazing reduction in brain fog and slightly less disturbed sleep. I’ve read about autophagy and I think it could really improve my health even further.

Having watched your (and other) videos on fasting, the emphasis tends to be on weight loss and my concern is that I don’t particularly have very much weight left to lose… but yet I really want to give intermittent fasting a try!

Is it possible to fast without invoking weight loss? Are there any particular guidelines available on fasting for autophagy and not weight loss?


Fasting is simply a part of a normal cycle – feeding and fasting. That is why there is the English word ‘breakfast’ or the meal that breaks your fast. You can’t break a fast if you are not fasting. If you are fasting more, you’ll lose weight. So limiting the fasting times or if your weight is too low, doing it less frequently allows you to fast without losing weight.

Dr. Jason Fung

Fat cells for life

Is it true that we keep all the excess fat cells we have ever generated and that lipolysis can only “shrink” the existing cells?


I believe so. Even for those people with minimal visible fat, there is some fat stores. In extreme cases, perhaps it may not be true, for all practical purposes, yes. It doesn’t make any difference clinically, though.

Dr. Jason Fung

Fasting causing high blood pressure

Asking about possible reasons why blood pressure would increase during fasting. Not asking for medical advice.

Attempted 72-hour fast which had to be stopped at about 58 hours due to hypoglycemic symptoms; sweating, shakiness, fast heart rate & palpitations, weakness and headache. High blood pressure was noted and it took two weeks for systolic pressure to normalize and about four weeks for diastolic.

Currently fasting was tried again and stopped at 36 hours due to sweating and heart palpitations. Next day, normal feeding, then the next day fasting attempted again which was stopped at 19 hours due to headache and elevated blood pressure.

I have searched for information regarding this and it is limited, most discuss benefits of fasting to help lower blood pressure.

Your insights are greatly appreciated,

Fasting causes certain hormonal changes. Insulin goes down but other hormones (the counter regulatory hormones) go up. This includes sympathetic tone, noradrenalin, cortisol and growth hormone. It is possible that your body responds exuberantly to these hormones to cause the symptoms of hypoglycaemia. It is also possible that you are becoming hypoglycaemic and developing symptoms. High blood pressure may occur due to these hormonal changes.

Dr. Jason Fung

(If you have difficulty fasting or experience symptoms like this patient reports, we at Diet Doctor would recommend that you refrain from fasting until you have been evaluated by a qualified health care practitioner.)

Q&A videos

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Intermittent fasting for beginners

A keto diet for beginners

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