Multi-day water fasting has been a recipe for better health since Greco-Roman times. Anecdotal evidence from church records during the Irish potato famine in the 1920s showed that children brought up during this period lived significantly longer than previous generations. Similarly, medical physician Emile Juste documented an almost a 100% eradication of “diseases of affluence” amongst his fellow prisoners within 3 months of beginning starvation diets during the WWII.

Luckily, new research over the last 15 years has shown that health-enhancing calorific restriction (CR)- meaning at least a 30% reduction in calorific input- can be emulated by less demanding, intermittent but regular fasting periods such as the well publicised “5:2”, where fasters limit calorie intake to 5-600 per day for 2 days per week.

Is this a strategy for losing weight?

I am asked this question at least once a week. My advice is always the same: fast for better health and weight loss will follow as an added bonus over the medium-term.

Typically, ‘faddy’ diets that require drastic calorie-cutting and the elimination of certain foods, prove unsustainable in all but the very short term. Initially, the starved body slows its metabolic rate to compensate for the restriction but when the dieter inevitably throws in the towel, a return to pre-diet calorie intake causes weight gain back to and beyond previous levels, initiating the classic ratchet-effect negative spiral. With IF, the freedom to eat as normal for 5 days per week makes calorie restriction much easier to stick with long term.

In practice, patients tend initially to compensate by eating more than they might otherwise do on non-fast days. However, appetite tends to normalise quickly: insulin sensitivity and hormone balance improves, vitality increases and, possibly most important of all, appetite is better-regulated as bad habits and self-reinforcing sugar high/lows fade and the body begins to crave higher quality nutrition. The end result is at least a 30% reduction in weekly calories which are also of better and more concentrated nutritional value.

What does 600 calories mean in practice?

Online searches are flooded with misinformation about IF. One classic mistake is the recommendation to have low calorie but protein-heavy foods on fast days such as egg-white omelettes, ‘low fat’ cheesy things and variations on chicken, turkey and fish dishes. However, much of the latest research points to evidence that the effects of CR via certain hormonal pathways (such as IGF-1) are almost fully negated if protein is ingested.

So what does IF mean to me? On fast days, I stick just with my morning coffee (sorry- but that will be something to eliminate sometime in the distant future!). Lunch consists of as much organic, seasonal, steamed veg dressed with garlic, extra virgin olive oil and a squeeze of lemon or a large seasonal salad, including but not limited to, green leafy veg, fennel, grated carrot etc. Depending on how my work day went, dinner time means either no food at all or some silken tofu with spring onion or alternatively, some home made veggie soup followed by a soothing bath and/or a calming meditation then a recuperative, early bed time with dreams of a huge breakfast! In practice I awake early, take some exercise and breakfast is of normal size and content (live Greek yogurt, ground nuts and seeds, a glug of honey and some seasonal fruit)!

Conclusion

This is the nuts and bolts of IF in the 21st century- psychological well-being, the breaking of bad habits, the creation of virtuous nutritional/lifestyle habits and greater mental and physical awareness. There is a mountain of cutting edge evidence on the PHYSICAL health benefits of CR and IF so tune in to PART II of this article in a blog post next week. Thanks for listening.

By Christian Di Giorgio