Calorie restriction isn’t new. Many weight-loss strategies are built around the premise that a calorie deficit is what is needed to lose pounds. And it’s true. Consuming more than the quantity of calories your body needs will only lead to a surplus, which results in weight gain over time. Weight loss, and maintaining a healthy weight, has long been known to benefit our health. It increases longevity and decreases the risk of many chronic diseases. A new study now shows that in healthy adults, calorie restriction further advances those benefits, again making the case to reach a healthy weight and build a lifestyle that supports maintaining it.
Regardless of how it happens, the direct benefits of weight loss are numerous. Even relatively modest amounts of weight loss can result in positive health benefits. According to a review study by D.J. Goldstein at Indiana University School of Medicine, even if you only lose less than 10% of your body weight, you can see a substantial improvement in markers associated with chronic disease. These include blood sugar control, lower cholesterol, and lower blood pressure- each responsible for a huge number of deaths every year.
Among studies that directly measured longevity (e.g. life expectancy), modest weight losses resulted in a significant increase in longevity when comparing people who lost a modest amount of weight to people who did not lose weight. This lends further support for the theory that even a little bit of lost weight can go a long way towards improving your health.
While calorie restriction is a long-standing method of losing weight, this study, published in Natural Aging, is the first-ever randomized controlled trial that looked at the long-term impact of calorie restriction. Funded by the National Institute on Aging, part of the National Institutes of Health, the study included 220 adults. Participants were randomized to cut their caloric intake by as much as 25% (500 calories for people who generally consume 2,000 calories a day), or to make no changes to their diet. The participants had a body mass index, or BMI, ranging from 22 to 27.
People in the calorie-restriction group, as opposed to participants that did not cut calories or receive behavioral diet counseling as a part of the study, ended up only cutting around 12% of their calories. Dr. Evan Hadley, director of the geriatrics and clinical gerontology division at the National Institute of Aging, said “. . .that 12% was enough to have significant change.”
The researchers found that people who cut their calories slowed the pace of their aging by 2% to 3%, compared to people who were on a normal diet. This was based on an algorithm that was built from data over a period of 20 years from 1,000 people whose organ function was measured as they aged.
While the results are promising- reach and maintain a healthy weight while calorie restricting- weight loss maintenance results are dismal over the long-term. Many people pursue weight loss through a variety of methods, but few can maintain the results. In fact, studies including one from the University of Pennsylvania’s Weight and Eating Disorders Program, show that 65% of dieters return to their pre-diet weight within three years and 5% of people who lose weight on a restrictive diet (such as liquid or no-carb diet) keep the weight off.
Even though the stats seem discouraging, experts agree that picking a method (whether a specific plan or a more flexible option, as we shared here), having parameters to follow does increase the rate at which people maintain the weight loss. After all, 65% don’t maintain the weight loss, but 45% do– with consistency, routine, and slow (but intentional!) shifts in lifestyle adjustments. You can read more about whether diet plans work in this post.
The key takeaway from this study is that we have the tools to slow our aging and boost our health. Additional studies need to be done to explore how long the benefits of calorie restriction hold. But it cannot be disputed that reaching a point in our wellness journey that includes being of a healthy BMI has many other benefits beyond decreasing longevity. Decreasing the risk of many types of cancer, lower risk of cardiovascular diseases and diabetes. Healthier gut. Improved brain health. Less pain. Better sleep. All of these are benefits of reaching and maintaining a healthy weight, and increasing longevity is yet another reason to take that first step towards improving our health.