There may be no upper limit to how rich you’d like to be, but there’s definitely a limitation for thinness. Having a body mass index (BMI) below 23 (less than about 55 kilos for a 160cm woman) is linked to greater mortality than being a few kilos heavier, a team of researchers discovered when they examined hundreds of studies with more than 30 million participants. This was true even when they excluded people who might’ve been thin because they were already sick. Plus, sinking to a too-low BMI can make you feel awful. (It’s important to note that BMI has been criticised as a flawed measurement, in part because it doesn’t differentiate between fat and muscle, categorising people with a lot of muscle as ‘overweight’, and it doesn’t consider ethnic differences in body type.)
If low weight equalled good health, dropping kilos would automatically make people healthier – but that’s not what happens. Dr Hunger points to a meta-analysis that found that, even after dieters lost weight, their blood pressure, glucose and other blood markers weren’t significantly better when they were reevaluated two years later. Heavy people may make health gains when they’re put on a weight-reduction plan, but participants in many weight loss trials are urged to exercise – which other scientists suggest was more likely a health driver than the reduction of kilos. WEIGHT IS MORE COMPLEX THAN ‘KILOJOULES IN, KILOJOULES OUT’ “So many things go into the weight you are,” Dr Himmelstein says. Genes, ethnicity, medicines you take, where you live, your income and how much you sleep all play a role, even if most doctors focus only on kilojoules.
Weight is so complex that even longtime researchers don’t yet understand all the variables involved. People might be heavier because food is so easily available. Or maybe it’s the larger dinner plates and portions we serve compared with 30 years ago. In the US, Dr Barbara Corkey, who specialises in obesity research, is intrigued by the notion that chemicals used in farming, additives in processed foods and/or other toxins that make their way onto your plate may cause your body to erroneously release too much insulin, a hormone that makes you want to eat more. Dr Corkey suggests that it may not be that obesity brings on problems like insulin resistance, but that unnaturally high insulin levels lead to obesity and insulin resistance.
Dieting can help you trim kilos, but keeping them off is another story. The low nutrition levels and excessive exercise of many weight loss plans aren’t sustainable, says Dr Hunger. Plus, when you cut back on kilojoules, your metabolism slows to a crawl. “Your body’s biological architecture doesn’t understand what the thin ideal is – it’s doing all it can to protect you from what it perceives as famine,” he notes. The answer? Cardiologist Dr Ruwanthi Titano says: “Rather than make a drastic temporary change for a short-term goal, focus on small, sustained changes, such as eating more plant-based foods and less red meat and processed fare.”
Even thin people benefit from ditching the focus on weight, Dr Himmelstein says. A lot of brainpower goes into monitoring kJs or carbs, she says – energy you’d be better off spending elsewhere. “Instead of trying to shrink your body, start to appreciate everything it does for you,” Dr Hunger suggests. You’ll be healthy and feel good no matter your dress size.
If low weight equalled good health, dropping kilos would automatically make people healthier – but that’s not what happens. Dr Hunger points to a meta-analysis that found that, even after dieters lost weight, their blood pressure, glucose and other blood markers weren’t significantly better when they were reevaluated two years later. Heavy people may make health gains when they’re put on a weight-reduction plan, but participants in many weight loss trials are urged to exercise – which other scientists suggest was more likely a health driver than the reduction of kilos.
Most people with high body weight have a story about how their doctor judged or blamed them or didn’t listen, says Dr Himmelstein. It makes women avoid going to the GP because they don’t want to be fat-shamed, and then miss out on treatment or early detection. In other cases, health complaints that have nothing to do with weight are inaccurately blamed on a person’s size, so patients don’t get the right treatment. In this way, doctors’ bias can make people sicker – which might then add to the perception that all who are large-bodied are unhealthy.
