Look around the bookshops and read some of the reviews for the latest books on weight loss and there’s a new buzzword on offer. It seems the genes you inherit from your parents change the way your body absorbs fat and carbohydrates. Gone are the days when a one-size-fits-all diet would sell like the proverbial hot cakes (unsweetened, of course). Now we are into the idea of personalized diets with DNA kits and gene testing offered as the way of designing the most effective way for you to lose those unwanted pounds. Except, there’s no science to support any of these claims. Myths help separate you from your money. The truth remains boring and does not sell many books.

Let’s start with the facts. The science of genetics has been around for centuries. Farmers, sports fans and governments have been selectively breeding animals (and plants) for their taste, speed or killing abilities. The results can be seen everywhere you buy food, on the race track, in the police and military compounds, and so on. There’s nothing new in aiming to select characteristics to transmit through the generations. And that’s where the science stops and the science fiction takes over. Although some scientists can now identify individual genes that may contribute to different characteristics, there’s no such thing as gene splicing - no designer babies for us humans to order - and no proven link between any combination of genes and human body weight.

Human body chemistry stays the same no matter what genetic make-up you have. What does change, and sometimes quite dramatically, is behavior. If you travel back to a time when people ate less processed food in smaller quantities, you find most children grew up thin. Now look around. Children are surrounded by peers and authority figures who all eat large portions of unhealthy processed food and the children get overweight. This has nothing to do with genetics. This is socialisation in a country that eats too much unhealthy food.

Using genetics is an excuse when people fail to keep to a diet. They claim they cannot lose weight because their genes make them big. They are then suckered when they see claims that only by paying for gene testing can an effective diet be devised for them. This is a sad state of affairs. You can only lose weight by making lifestyle changes. You have to eat less and exercise more. If you feel hungry when you start a diet, a drug like phentermine is available to control the hunger pangs. Phentermine has been on the market for some fifty years and remains the scientifically proven way of controlling your appetite. So long as you avoid feeling hungry, it’s easy to stay on the diet and feel the weight fall away. Overall, you are following a simple rule. So long as you burn more calories than you eat, you will lose weight. If this means increasing your activity rate, rise from your couch and go for regular brisk walks. A calorie-reduced diet combined with exercise and supported by phentermine is the one-size fits-all-genetic types approach to weight loss.