Effect of Weight on Mental HealthWeight is a marker of health, but it’s not the only one. While we know that excess weight is associated with certain health conditions, we don’t always know why.

To that end, prescribing weight loss as a solution to mitigate health risks can often be ineffective and even harmful—a more effective approach might be to focus on behavior changes (like exercise, healthy eating, and so on) over modifying a physical attribute.

Most importantly, while weight can be an important piece of information, it isn’t the conclusive measure of your wellbeing, your life, or your worth. Having excess weight is not a moral failing, and it’s dangerous and cruel to treat it like one.  What’s the worst thing you could possibly do for your health? If you were to look up what factors increase your risk for various diseases, you might assume the answer was simply: be fat.

Potential Health Consequences

In fact, the Centers for Disease Control (CDC) links obesity to at least 13 potential health consequences, including high blood pressure, type 2 diabetes, coronary heart disease, stroke, gallbladder disease, sleep apnea, osteoarthritis, poor cholesterol numbers, chronic pain, mental illness, several cancers (including endometrial, breast, colon, liver, kidney, and gallbladder cancers), poor quality of life and—of course—death.

This long list of ailments associated with obesity—along with the fact that, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) approximately 70 percent of the adult population in the U.S. is overweight or obese—has led to decades of news stories and reports surrounding our “obesity epidemic.”

When it comes to why people of larger sizes are at increased risk for various health conditions, the research is often less clear. No matter how much information we have about weight as a marker of health, it doesn’t always give us specific answers about how best to mitigate health risks. Just because excess weight is in fact associated with increased health risks doesn’t necessarily mean that focusing solely on weight loss is the best solution.

Most of the research on weight and health relies on body mass index (BMI) to categorize people based on weight. Your BMI is calculated by taking your weight in kilograms and dividing it by your height in meters squared. A “normal” or “healthy weight” BMI is one that’s between 18.5 and 24.9. Any number below that is considered “underweight.” At 25 and above, you’ll get into “overweight” territory, and once you hit 30, you’re considered “obese.”

BMI and Mental Health

BMI is particularly useful for looking at large groups of people to identify trends, which researchers often then examine in further detail using additional markers of health, such as blood pressure. The thing is, we know that BMI is an imperfect measure of health. Research shows that you can have an obese BMI and be metabolically healthy, and you can have a normal BMI and be metabolically unhealthy.

BMI may be an easy way to categorize weight in population-based studies, but it’s not a great way to assess an individual’s health risk without digging further. It doesn’t take into consideration things like muscle mass, body fat percentage, or where and how your body stores fat.

Research suggests that people with mental illnesses, such as depression and anxiety, also have higher levels of C-reactive protein, a marker of inflammation in the body. So mental health issues associated with obesity and weight stigma may be contributing to the higher levels of inflammation seen in people with higher BMIs.

Randi Fredricks, Ph.D.

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