How to choose the best diet for you…

Horizon's Dr Chris van Tulleken and Professor Tanya Byron reveal new ideas about why we put on weight - and how to take it off again

Constant Cravers

“Constant Cravers are hungry the whole time,” says van Tulleken, “and like to snack on things high in sugar and fat.” They enjoy their food and think about it a lot, grazing throughout the day. Soon after a hearty lunch, this group was offered a range of foods and given a gadget that they squeezed to measure how tempting they found each item. The Cravers all wanted naughty-but-nice sausage rolls and cupcakes more than the other groups.


The science

Certain genes interfere with the brain’s understanding of our fat reserves, explains Dr Giles Yeo, a genetics researcher at the Medical Research Council. If it thinks we have less fat than we actually do, it tells us to keep on eating – a basic survival mechanism. All the Constant Cravers tested positive for these genes.

Right diet

Losing weight is hardest for Constant Cravers. The answer is intermittent fasting – better known as the 5:2 diet, when you eat normally (but healthily) for five days a week and then reduce calorie intake to 800 on the other two days. This makes the body burn up its fat stores.

Result: Average weight loss 1st 1lb
For Sharon Ferreira, “Food is like a secret partner that no one else knows about, nobody else sees me with.” Like all Constant Cravers, Sharon found the diet a challenge – she lost 6lb – but knowing this is related to her genes has helped her to understand why. 


What’s the Right Diet for You? A Horizon Special begins on BBC2 tonight (12th January) at 9.00pm