A recent study from the University of Birmingham's Institute of Applied Health Research suggests that metabolically healthy and obese adults are still at a greater risk for heart disease when compared to individuals with lower weight.
A metabolically healthy adult is an adult who does not suffer any metabolic abnormalities such as diabetes, high blood pressure, and high cholesterol — which is the case for many overweight or obese adults. Because of this, in recent years, many researchers have been reluctant to connect a lower weight to more positive health outcomes.
Which makes this study confusing. How could metabolically healthy obese individuals still suffer poorer health if weight doesn’t matter?
The study followed two groups of metabolically healthy participants: one group with a “normal” body mass index (BMI) and another with an “obese” BMI. After over five years, the researchers checked back in with participants and discovered that the obese participants had a much greater chance of heart disease after the five-year period than normal weight individuals.
“We conclude that obese patients, irrespective of their metabolic status, should be encouraged to lose weight,” said senior author and public health physician, Dr. Krish Nirantharakumar.
However, there are a number of studies suggesting the exact opposite — that recommendations for weight loss could cause adverse health effects, rather than positive ones. “The success rate of intentional weight-loss efforts is 5 percent or less, by most researchers’ accounts,” Christy Harrison, MPH, RD, CDN told The Daily Meal. “So for 95 percent or more of people, all diets are yo-yo diets. And we know yo-yo diets negatively affect people’s health outcomes.” Yo-yo dieting, which entails attempting weight loss only to gain the weight back again, has been shown in multiple studies (such as this one) to increase the risk of coronary heart disease. So, in Harrison’s words, “Prescribing weight loss is not ethical healthcare.” It endangers those attempting to lose weight.
So then how is it the study’s authors came to this seemingly contradictory conclusion? It seems that we can’t be overweight but we can’t try and lose weight either.
Well, the results of the study might not prove what they claim to.
“The study didn’t control for weight stigma and weight cycling,” explained Harrison to The Daily Meal, “which are two known independent risk factors for heart disease.” So these factors, including previous attempts at weight loss and the potential negative effect on obese individuals’ mental health from experiences like bullying and shaming during childhood, lower salaries, and criticism from doctors, could have set up the obese participants for heart failure before the study even started.
“Experiencing this stigma independently raises people’s risk of chronic diseases including heart disease — regardless of actual body size,” says Harrison. “It also results in people delaying or avoiding going to the doctor, which can result in poorer health outcomes down the line.”
The study also failed to account for healthful behaviors during the period of the study. The metabolically healthy obese individuals could have completely different dietary habits and lifestyles than the participants with a normal BMI, further skewing results.
“The researchers didn’t determine whether the study participants were dieting and bingeing versus eating intuitively and in balance; they didn’t determine whether participants were engaging in regular physical movement or not; they didn’t control for whether the participants had access to compassionate healthcare that supported their actual health instead of focusing on their weight and reinforcing weight stigma,” explains Harrison. “And all of these things can affect people’s health outcomes, again independently of body size.”
Health At Every Size (HAES) is a concept that is gaining traction in clinical fields, and naturally its proponents oppose the conclusions of the University of Birmingham study. HAES suggests engaging in health-promoting behaviors such as healthy eating and regular movement without pursuing weight loss. Studies such as this one show that HAES approaches have resulted in better health outcomes than the traditional weight-focused paradigm.
Another reason not to run out and start a crash diet: The University of Birmingham’s study results also implied that underweight individuals had much greater heart-related risk — this aspect of the study, however, has not been widely reported on.
Essentially, an interpretation filtered for weight bias suggests that other factors might be contributing to the negative effects on health — further proof that a focus on weight is yet another thing you assume about healthy people that just isn’t true.