BBC Horizon’s – Eat, Fast And Live Longer

Another great programme from BBC Horizon presented by Dr Moseley. He starts off the programme by following the oldest man to complete the London marathon…a 101 yr old sikh who is healthy and takes no medication…the typical 65 yr old european takes 6 pills a day! The centenarian attributes his good health to his diet and more specifically his small portion size…about half of a normal adult”s.

This is not the first time that caloric restriction has been linked to longevity. In the 1930s, during the great depression in the US, although there were widespread food shortages…surprisingly life expectancy increased by 6 years. During the same period scientists at Cornell University found that animals on restricted diets lived longer.

Dr Moseley had a keen personal interest in the subject because of the threat of disease due to elevated blood sugar and cholesterol. He traveled the US speaking to the most eminent specialists in the field in a quest for a solution to his health problems. His first port of call was Professor Luigi Fontana from Washington University and Salerno Schools of Medicine. Prof Fontana advised a diet low in calories but high in nutrients and introduced Dr Moseley to Joe. Joe was in his 50s and had been on 1900 kcal/day for about 10 years. His body fat was 11.5% whereas Dr Moseley”s, also in his 50s, had a body fat % of about 27. Although the benefits were clear, Dr Moseley wanted to understand the mechanism in the hope of being able to draw the benefits without having to do any of the hard work! This is one of the reasons I like his programmes…his attitude is typical of the average european (or american)…we want results quickly, with as little effort as possible…sound familiar?

He then met up with Professor Valter Longo at the University of Southern California. Prof Longo showed him a special mouse…about half the size of a normal mouse…but incredibly it had a lifespan that was 40% longer…the equivalent of 120 human casino jameshallison years! The mouse had been genetically modified to have low levels of the a growth hormone called Insulin-like Growth Factor 1 (IGF1). IGF1 is thought to be the link between calorie restriction and longevity. There are about 350 people worldwide who have genetically inherited low levels of IGF1. Their condition is named Laron syndrome and although some of them smoke and eat what they want, amazingly they don”t get diabetes or cancer! Low levels of IGF1 seem to increase cell repair and decrease cell division (which probably accounts for their extremely small stature).

Protein has been found to increase our metabolism and put us in “go-go” mode but the downside is that it decreases cell repair. Three things can help decrease levels of IGF1: decreasing calorie intake, decreasing protein intake and lastly, the most effective way…is by fasting. Fasting can dramatically reduces levels of blood glucose and IGF1 within as little as 24 hrs. Obviously fasting can be dangerous and should only be undertaken if in good health and under close medical supervision. So Dr Moseley decided to give it a go for 3.5 days. He only allowed himself water, black tea and a 50 kcal soup each day. As expected, his blood sugar decreased significantly and his IGF1 levels halved. Unfortunately, the effects are only temporary and one would need to decrease protein intake and fast every couple of months to maintain changes…not for Dr Moseley, so he continued his search…

Dr Krista Varady from the University of Illinois at Chicago had a much more palatable proposition…eat as much of whatever you want on one day and eat a reduced amount of whatever you want the following day…feed day, fast day, feed day, fast day, etc. It”s called Alternate Day Fasting (ADF). On the fast days women are advised to eat 400-500 kcal and men 500-600 kcal. Preliminary trials with overweight subjects are showing promising results including weight loss, lower levels of bad cholesterol and fats in blood and decreased blood pressure.

Lastly, Dr Moseley paid a visit to Dr Mark Mattsen from the National Institute on Aging in Baltimore. He has conducted animal experiments on intermittent fasting and has found that it postpones the development of Alzheimer”s and senile dementia like diseases. Sporadic bouts of hunger seem to trigger the growth of new neurones! In evolutionary terms, this would have provided a survival advantage in times of famine. Intermittent fasting has better effects on the brain than daily calorie restriction. Dr Mattsen suggested alternating 5 days of normal eating with 2 days of fasting. So Dr Moseley gave it a go for 5 weeks. On the normal days her took in around 200 kcal and on the fast days he ate about 600 kcal. Please bear in mind that normal calorie intake is based on sex, height, weight and activity. The results were extremely impressive. He managed to lose 1 stone and decrease his body fat from 27% to 19%! His blood sugar levels decreased to within normal limits, his IGF1 levels halved, his total cholesterol decreased and his good cholesterol increased. I assume that although he could have eaten whatever he wanted, he was sensible about it.

Dr Moseley ended the programme by saying that it was “the most interesting journey that I”ve ever been on…and I”ve never said that before”.