Weighing a few extra kilos can help us live longer: study
It was news that had us reaching for a second slice of cake – a study from the University of California in the US found that those who were most likely to live to 90-plus carried a few extra kilos in their 70s.
It may go against everything we’ve been taught, but experts say that in some cases, being overweight (not obese) could be good for you. But before you cheer this news with a cheese plate, read on.
The idea that a little fat might be healthy isn’t new. In fact, the theory, called the ‘obesity paradox’, has been researched for more than 20 years. Work started after it was discovered that overweight people with heart problems had better outcomes than underweight patients, and even fared better than those with a healthy BMI.
“Thin people get less disease in general, but when a thin person gets cardiovascular disease, they do much worse than someone a bit heavier,” says US cardiologist Dr Carl Lavie, author of The Obesity Paradox, and one of the first experts to explore the idea.
The link isn’t just with heart issues, though. Researchers at Canberra’s Australian National University (ANU) found that a higher weight in seniors was linked with a reduced thinning in the part of the brain that’s at risk of cognitive decline. Meanwhile, a study at the University of Hull in the UK found that overweight (but not obese) type-2 diabetes patients were more likely to outlive slimmer patients.
Meanwhile, sepsis, strokes and heart surgery have a higher rate of survival in slightly heavier people. So how could this be?
Through the ages
Maybe we’re not supposed to be thin for life, particularly as this trait is rarely seen elsewhere in nature as bodies adapt to the changing demands of ageing.
“It doesn’t happen in any other mammal, so why would it happen in humans?” asks Professor John Dixon from the Baker Heart & Diabetes Institute in Melbourne. “In fact, there’s a clear U-shaped relationship between BMI and mortality.”
In other words, it seems that being a little heavier when you’re a child is protective and it’s also good to be slightly heavier as a senior. But it’s better to maintain a sensible weight in between.
“This U-shaped relationship appears in all aspects of health,” Dixon says. “A little alcohol seems to be more protective than too much or none. A moderate level of exercise is good for us, but none or excessive amounts is detrimental. Even salt is good for us in a moderate amount, but too much, or none at all, is bad.”
Fat or fiction?
A likely theory for the paradox is that as we gain weight, we gain small amounts of muscle, too.
“Higher muscle mass and better muscular strength are a key sign for survival of serious illness,” Lavie says. “Some thin, elderly people are physically weak with low muscle mass and low resistance to disease.”
Other experts warn that we still have to be sceptical about fat being protective. “I don’t think the evidence is there to say that the obesity paradox exists,” Professor Anna Peeters of the School of Health and Social Development at Melbourne’s Deakin University says.
“Yes, there’s a correlation between carrying some extra weight when you get older and increased longevity, but that doesn’t necessarily mean the extra weight is protective.
It could just mean that those not carrying it have another risk factor that wasn’t identified and controlled for in the trials.”
Even those who believe the paradox exists say it shouldn’t be used as an excuse to get too heavy. “Some people have the impression it means it’s better to be obese, which isn’t the case,” Lavie says. “Many obese people with cardiovascular disease may have never developed heart disease had they remained lean – and especially if they’d stayed lean and fit.”
A US study published in the journal JAMA Cardiology backs this up. It found little difference in longevity between normal weight and overweight people but the latter had a higher risk of cardiovascular issues, and obese people were more likely to die of heart complications.
“I get a lot of patients who ask, ‘Why do I need to lose weight if research says I’m going to live longer?’” said the study’s author, cardiologist Dr Sadiya Khan. “I tell them that losing weight doesn’t just reduce the risk of developing heart disease, but other diseases like cancer, too. Our data shows you’ll live longer and healthier when you’re at a normal weight.”
Know your risks
Ask yourself the following questions to work out where you may need to make some changes
How old are you?
Carrying a little bit of fat may be good as you reach your 70s and 80s, but it’s better to be a normal BMI in your younger years as it dramatically lowers your risk of heart disease and diabetes. Plus research from ANU found that those who gained extra weight in middle age had a greater thinning of the brain’s grey matter.
How much weight are you carrying now?
“If you’re a normal weight, don’t actively try to gain any extra,” Lavie says. If you’re past middle age and just a few kilos overweight, perhaps relax about losing them and focus on raising your fitness level instead.
Remember that moving into the obese range isn’t recommended.
Check your BMI using an online calculator: under 18.5 is considered underweight, between 18.5 and 24.9 is normal weight, between 25 and 29.99 is overweight, over 30 is obese.
Male or female?
Gender may play a role. The study published in JAMA Cardiology showed that overweight middle-aged men lived the same amount of time as their normal-weight counterparts, but normal-weight women lived 1.4 years longer than overweight ones.
It may be that excess weight is therefore less of a problem for men.
Fit and healthy?
Someone who carries extra weight but exercises regularly will be healthier than someone who weighs the same and doesn’t exercise. “Fitness is definitely more important than fatness,” Lavie says.
“Those who are fit do better whatever their weight.” Eating well, drinking sensibly and not smoking are also going to help boost your health whatever your weight.
Where do you carry those extra kilos?
“Where you wear your weight matters,” Dixon says. Fat carried around your middle is unhealthier than fat around your hips and thighs. The easiest rule to remember is the circumference of your waist (determined as the point just under your belly button) should be less than half your height.
While we’re on the topic, here’s how fasting for just 24 hours can improve stem cells, plus how shivering and exercise both trigger same fat-burning effect.
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