What is the minimum calorie intake I can take to stop my body going into save mode?

[fedupwithme]

a friend is doing a reduced portion size eating plan but every 5th day she drops to a max of 500 cals. She says that is working for her because she's eating just enough on the "fast" day to stop her body triggering the fat storage mode

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Hi fedupwithme,

I would strongly advise you not to attempt to lose weight too fast. Very Low Calorie Diets should only be undertaken under medical supervision and are generally only used when the risk to a person's health from their excess weight is greater than the potential risks from the VLCD.

Intermittent fasting as a weight loss regime, e.g. the 'five-two' diet have become fashionable of late, though really the 'jury is still out' on these as there would seem to be inadequate reliable data available as to the medium and long term effects for people who undertake these.

I would only comment that many weight loss "fashions" have turned out to be only of use in the short term and have resulted in their users regaining the lost weight and often even gaining more than they lost.

Remember that weight loss is not just about calorie deficit, it's also about how you encourage your body to burn fat rather than store it and those processes - just like your feelings of hunger and satiation - are controlled by hormones.

My concerns / doubts about those sorts of approach are basically, it seems unwise to drop your blood sugar levels so severely every fifth day as such a drop is likely to hinder the fat burn process and also, I don't really see how such regimes address the underlying issues of what is causing you to have become fat in the first place, i.e. the "bad" eating and exercise/activity regimes.