Are new year diets doomed to fail?

Extreme diets - Grapefruit only

Some newspapers have claimed that we have evolved not to lose weight in winter. We take a look behind the headlines.

“If you have already broken your New Year’s resolve to lose weight, don’t be too hard on yourself,” said the Daily Mail. “Apparently we are programmed to overeat – especially in winter.” 

The Express said: “New research shows that humans have evolved a subconscious urge to over-eat in the colder months of the year.”

It might sound like a great excuse to finish the leftover chocolates. But, let’s take a closer look at the science behind the story. This news coverage was based on a study from the University of Exeter, which found that animals – humans included – have been programmed by evolution to eat more during the winter months to protect us in the winter months.

Lead scientist Dr Andrew Higginson said: "All animals, including humans, should show seasonal effects on the urge to gain weight. Storing fat is an insurance against the risk of failing to find food, which for pre-industrial humans was most likely in winter. This suggests that New Year's Day is the worst possible time to start a new diet." 

If you have started to make healthy lifestyle changes for the new year then don’t use this as a reason to give up.

Victoria Taylor

The study suggested that being overweight is less of a threat to our survival than being too thin, so hearty meals and maintaining that spare tyre are simply our natural response to bitter weather. The conclusion that we should hold off on the diet until April was reached by mathematical equations to “model food consumption in an animal that minimises mortality by switching between activities that differ in energy gain and predation”. 

A major drawback of the study is that it was not based on any studies in humans. The study also seems to ignore the fact that humans have an evolutionary advantage – our brains. Nature might encourage us to lose weight in winter, but as conscious beings, we have other motivations. These might well tip in favour of the traditional New Year diet. It’s easy to think up reasons to avoid the dreaded diet, whatever time of the year. But it’s always a good time to start on a healthy, balanced diet. 

The BHF view

Our Senior Dietitian, Victoria Taylor, said: “This is a theoretical study based on modelling and so it shouldn’t be taken too literally. If you have started to make healthy lifestyle changes for the new year then don’t use this as a reason to give up.

“It might come more naturally to eat more fruit and vegetables and get outside in the summer months when a wider variety are in season and the weather is warmer, but we need to be mindful of our weight all year round. 

“So rather than hibernating on the sofa until spring comes around, think of ways that you can eat well and be active in the winter too. Try stewed fruits, vegetable soup and roasted root veg to make healthy eating more seasonal. Getting active around the house for example with cleaning or a home exercise DVD, are options to try when it’s dark and cold outside.” 

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