Alternate day ‘IF’ fasting on BBC

Last month’s Horizon TV programme on how to live longer, gain health and lose weight by eating less through intermittent fasting (IF), also called ‘alternate day’ fasting, having less protein and lowering insulin-like growth hormones is bang on target for healthy ageing and rapid weight loss. Here’s how it works and what to do. Find out more at

Readers of my newsletter, or latest book Ten Secrets of Healthy Ageing will be familiar with the reasons behind the benefits of modified fasting, which lowers blood sugar levels and insulin production. This, in turn, reverses metabolic syndrome and burns fat. The Horizon programme emphasized the need to bring down levels of insulin-like growth factor (IGF-1) to extend life and reduce disease risk. In Issue 55 I explained in detail how IGF-1 is associated with disease risk and, in Issue 61, why it is critical for health to keep insulin down. Horizon recommended eating less protein to bring down IGF-1, but failed to mention that the biggest promoter is dairy products.

This is why my low-GL diet, which is specifically designed to keep insulin down, includes very little meat or dairy products. Interviewing Mark Mattson, who features in our Healthy Ageing book, Horizon’s Michael Mosley tried fasting for four days, then modified intermittent fasting, namely eating 600 cals on two days a week. The total fast, although severe, is actually a good way to kick-start a metabolic and genetic shift towards fat burning. However, modified intermittent fasting is easier to do.

I explained how to do this in Issue 69 and also in Issue 65. The simplest way is to have two days a week on 600kcals a day by having two Get Up & Go shakes made with soya or oat milk and low sugar, low calorie berries, such as strawberries.This is under 300 kcals so you can have this twice a day. You can even add a teaspoon of chia seeds and up the protein, fibre and omega 3 content. Add a heaped teaspoon of a super fibre such as glucomannan (from konjac fibre), such as CarboSlow or PGX, will really fill you up. Get Up & Go is a powder made from a special blend of quinoa, brown rice and soya flour, giving an excellent quality of protein. This is balanced with carbohydrate, mainly from whole apple powder and a little xylitol, together with oat bran, rice bran and psyllium husks for added soluble fibre, plus sesame, sunflower and pumpkin seeds and some almond meal, cinnamon and natural vanilla for flavour.

In addition, it has added vitamins and minerals, including 50mcg of chromium and 1,000mg of vitamin C, plus all the B vitamins. This is my top recommendation because it also gives you a very good all-round intake of protein, low-GL carbs and vitamins and minerals and it fills you up the most, being high in soluble fibres – especially if you add more. On the days in between it’s good to follow my low GL diet principles explained in the Low GL Diet Bible, with one day off a week. So that’s two days modified fasting, four days low GL eating, and one day off. It’s best to have the day off after a fasting day.

The Horizon programme referred to the research of Dr Krista Varady of the University of Illinois at Chicago, who has found that there’s no real advantage of having a low-fat diet on that day off. While many have pushed for low-carb, high protein diets as the way to lose weight I’ve resisted because of the evidence of dangers associated with too much growth hormone. Anti-ageing skin fanatics have also favoured upping growth hormone, for example from colostrum-based skin creams, due to its anti-ageing effects on the skin. Again, I’ve remained sceptical. Body-builders try to up growth hormone by consuming lots of whey (dairy) protein and, sure enough, you do build bigger muscles but at what cost?

If your goal is to live long and be healthy it’s better to have lower IGF-1 levels, achieved by eating a more plant-based, less meat and dairy based diet. The key is to keep blood sugar levels stable, which means less insulin release. These are the key principles in my low GL diet. There is one ‘growth hormone’ exception, and that is exercise. Resistance exercise and sprinting/interval training does promote growth hormone naturally, but doesn’t switch off anti-ageing genes. In fact, it does the opposite. It’s very good for you, reducing disease risk and extending lifespan. Again, you want a balance between aerobic and resistance (muscle building) exercise. There’s lots of this in the Ten Secrets of Healthy Ageing book. If you want to get started I have a full free Special Report on Alternate Day Low gL dieting on and you can also join my Six Weeks to Success groups, which includes virtual coaching week by week at this site.