Nutrition: is being big a genetic destiny

Amanda Ursell

I come from a family of ‘large people’. Can eating well overcome what seems a genetic destiny to be big?
The answer is yes. If you watch your calorie intake and match it with your calorie needs, you can maintain a normal body weight throughout life, whatever your family’s combined vital statistics.

This can be more of a struggle for some than others and we all have to work within the parameters of the body shape that we have inherited. But it is possible to buck the trend within a family prone to weight gain.

New research, however, suggests that in future we may have a more sophisticated way of prescribing diets according to genetic make-up. This will help certain people to avoid obesity by tweaking the types of foods that they eat, not just relying on the calorie equation.

Work carried out by Dr José Ordovas at the Nutrition and Genomics Laboratory in Boston, USA, is leading the way. Ordovas has just shown how

people with a particular genetic configuration are more likely to put on weight if they eat more than 22g of saturated fat a day (very easily done if you eat fatty meat products, cheese, cakes, puddings and fast food), compared with those with the same genetic tendencies but who kept their saturated fat intakes below this level.

The problem, of course, is that we do not yet have widespread availability of gene testing, because it is still ferociously expensive to carry out. Until then, it is back to the same old drawing board, I’m afraid. Eat well, be as active as you can – but you can be fairly confident that future generations of your family will get much more tailored nutrition advice to help them to buck the trend.

I’m 44. Is there anything I can eat to help to keep my muscles toned as I get older?
We naturally tend to lose muscle as we age (about 2kg a decade). Ensuring that we perform daily strength-training exercises can certainly help to counteract this decline. A very good book called Strong Women Stay Slim by Dr Miriam Nelson, of Tufts University in America, is a worthwhile source of exercises that can easily be done at home.

What we eat may also help. As we get older, a mild but increasing acidosis occurs in our bodies, which accelerates the wasting of muscles. This process can, it appears, be slowed down by eating a diet rich in fruits and vegetables. These foods naturally produce alkaline residues that help to neutralise the acidosis.

In the UK we all know that we should be aiming for five servings of fruit and vegetables a day. In America the target is nine a day. The best advice is to do as well as you can, remembering that fresh, frozen, canned and dried all count.

Are ‘live’ yoghurts probiotic and do the ones that say they stop bloating really work?
Yoghurt is made by lactose, the sugar in milk, being fermented by bacteria into lactic acid. This acid causes the milk to take on a more solid texture.

The bacteria usually used to trigger fermentation are Lactobacillus bulgaricus and Streptococcus thermophilus. If the yoghurt you eat still contains these bacteria, it can be defined as “live” – it still contains live bacteria, but these are subsequently digested once the yoghurt is eaten.

Probiotic bacteria are another thing altogether. These are special bacteria that are added to the yoghurt once it has been made. They must be proved to be able to survive digestion and to move, unchanged, into the colon, where they must then be shown to be able to latch on to the colon wall and exert some kind of physiologically beneficial effects.



Nutrition: is being big a genetic destiny