Why having weight loss as a New Year’s resolution may be bad for your health

A version of this commentary appeared in the Winnipeg Free Press, Vancouver Province and the Waterloo Region Record

Every year many Canadians will pledge to start the year off by losing some weight to get healthier.  There is plenty of evidence to show that losing weight can improve your blood pressure, blood sugar and even your cholesterol rates.  However, losing weight and being healthy are not the same thing.

You can get healthier without losing weight, and for some, losing weight may actually be bad for your health.

When an individual loses weight, they will lose fat mass, but some of that weight loss comes from muscle mass.  Muscle mass burns many more calories than fat, and accounts for a large proportion of the energy we burn even at rest.  In other words, loss of muscle mass may be counterproductive to long-term weight loss goals.

Also, when an individual loses weight, their body will try to protect the body weight by decreasing the number of calories the body burns (a change in ‘metabolic rate’).  These two factors help to explain why so many of us may find it difficult to continue to lose weight after a while, and why over 90% of individuals who lose weight will regain that weight within a few years.

If that isn’t bad enough, there is evidence to suggest that individuals who try to lose weight and repeatedly fail will have greater weight gain over time than individuals who do not try to lose weight at all.  This weight cycling or yo-yo dieting has also been linked to higher rates of diabetes, cardiovascular disease, cancer and higher death rates.  Reasons for this are still unclear, but research suggests that unless you can keep the weight off, dieting may have negative effects on your health.

Why is it so difficult to maintain weight loss over the long term?

One of the reasons is that many individuals approach weight loss as a quick fix.  Done correctly, weight loss should be a lifelong process and not a short term goal.  For example, after losing the weight, an individual cannot return to the lifestyle that led them to their elevated weight in the first place since this would only lead them back to their original weight — or higher.

Those who struggle with their weight need to explore underlying causes first, which will help to explain the reasons for their struggle.  Factors that may contribute to weight gain include certain medication use, exposure to environmental pollutants, too much ambient light exposure or sleep deprivation.  But even stressing about your weight can trigger cravings for high fat and high sugar foods and exacerbate weight gain.

There is some good news, however.

There is actually a subset of the population who appear to be perfectly healthy despite an elevated body weight.  Research is undecided about the long term health consequences for these individuals, but it has been suggested that weight loss may not benefit their health.  In fact, one important study shows that weight loss may make their health worse.

So, thinking of losing weight in the new year?

Consider first why you want to lose weight and whether or not you have the right approach.  All weight loss methods require time, effort and/or money and the health benefits aren’t guaranteed even if you are successful in achieving your weight loss goals.  So what should you do?

Here’s what the research to-date tells us.  If you want to start the new year off by getting healthier, get active, eat better, try not to gain any more weight and don’t stress about the small stuff.  If you want to lose weight, try something that you can sustain for the rest of your life — and remember that slow and steady wins the race.

Jennifer L. Kuk is an expert advisor with EvidenceNetwork.ca and Associate Professor in the School of Kinesiology and Health Science at York University.

January 2013