Still battling those lockdown pounds? Struggling to fit into your summer clothes? If you’re a midlifer staring despairingly as the numbers on the bathroom scales continue to rise, then you are far from alone.
New research from Cancer Research UK, published in May, suggested that if current trends continue, seven in ten Britons will be classed as overweight or obese by 2040 — and it’s a problem, particularly as we move into midlife and beyond.
And a recent study in Finland found that piling on the pounds in middle-age makes you old before your time — with obese 55-year-olds having health problems not normally seen until people are in their 70s.
Yet according to the Health Survey for England 2019, only 13 per cent of people aged 16 to 24 are obese, compared with 33 per cent of the 45 to 54 age group.
Weight peaks between 65 and 74, with 36 per cent being obese and a further 39 per cent overweight. After 75, things change slightly, with 45 per cent being overweight and 26 per cent obese. This trend has catastrophic effects on health, raising the risk of cancer, type 2 diabetes, depression and dementia.
But why do we gain weight in midlife?
For years, the culprit was thought to be a slowing metabolism — but new research suggests that this is not the case. In a groundbreaking study last year, scientists measured the metabolic rates of 6,400 people aged from eight days old to 95 years old and found that metabolism does indeed change with age — but not when you might think it does.
The study revealed that our metabolism — the amount of calories we burn for our size — peaks when we are just 12 months old. After this, it slows by about 3 per cent each year until we reach our 20s, when it levels off into a new normal and stays ‘rock solid’ until we are 60. This means that a woman of 50 will burn calories as effectively as a woman of 20.
Professor John Speakman, a biologist at the Institute of Biological and Environmental Sciences at Aberdeen University, one of the authors of this study, published in the journal Science, told Good Health: ‘One surprising thing was there was no fall in metabolic rate in midlife.
After 60, our resting metabolic rate declines by about 0.7 per cent a year until, by the age of 90, our metabolism is 26 per cent lower.
Fellow researcher Herman Pontzer, an associate professor of evolutionary anthropology at Duke University in the U.S., said: ‘Our paper provides more support for the view that our metabolism is hard to budge. Our bodies follow a programmed course throughout our lives, and there’s not a lot that we can do to change the energy burned per day.’
Professor Speakman admits that, despite this, ‘many people struggle with weight in their 40s’. So what is going on? The uncomfortable truth appears to be that we get fatter because we consume too many calories — but we often just don’t realise it.
This tallies with the findings of a study published last week, in the journal Cell, which found that naturally skinny people are no more active than the rest of the population: they simply eat less.
And middle-age spread, it seems, is a simple accumulation process. As Professor Speakman explains: ‘The amount you have to overeat each day to put on 20 kg (44 lb) over 15 years is not much.’
The process begins, he says, as we ‘eat and drink more’ as ‘we become wealthier and have more disposable income’ and that ‘increased alcohol consumption could be another factor’.
What does appear to encourage middle-age weight gain, however, is the menopause. Studies show that while the menopause doesn’t actually increase overall weight, it does affect the amount of fat versus lean tissue that a woman has — and where that fat is stored.
Postmenopausal women have more visceral fat independent of age, which means that menopause was the likely reason, according to Dr Sarah Berry, an associate professor in nutritional sciences at King’s College London and lead nutritional scientist at the health science company ZOE.
One reason may be that the menopausal women ate more sugary food and, according to Dr Berry’s research, the menopause changes the way sugar and fats are handled by the body. Previous studies have linked these changes to the fall in oestrogen, a hormone that regulates fat distribution and insulin sensitivity. Genetics, too, play a role. Identical twins have virtually identical weights as adults even if separated at birth.
Dr Giles Yeo, a neuroscientist at Cambridge University who studies the links between obesity and genes, says that genes may affect our appetite — meaning that some of us are more likely to crave fattening food.
So what can we do if we pile on the pounds? Sally Norton, an NHS gastrointestinal surgeon, says her key recommendation is to remove ‘chemical foods’ from our diets. A seminal study by the U.S. National Institutes of Health in 2019 found that people eating largely ultra-processed foods consumed an average of 500 calories a day more than those eating a diet of unprocessed foods. In two weeks, those eating ultra-processed foods gained 2lb, while those eating natural foods lost 2lb.
Sleep, too, is important, says Sally Norton, as sleep regulates the balance of hormones that affect hunger. She recommends aiming for seven hours a night. A study at King’s College London in 2016 found that sleep-deprived people ate 385 more calories a day. When forced to go through their day after less than five-and-a-half hours of sleep, they were more tempted by unhealthy food.
Exercise such as running can help but you have to work hard, as studies suggest that to prevent midlife weight gain, runners must increase their weekly distance by about 1.4 miles a year. So someone running ten miles a week at 30 needs to do 24 miles a week by 40 to stay slim.
Meanwhile, U.S. research shows one to two hours a week of weight training reduces the risk of obesity in the following six years by 30 per cent in both men and women.
The bottom line is if you want to keep your bottom in check in midlife, stop blaming your metabolism.