The Ideal Amount of Exercise Is Less Than You Think (and Better for You Than Constant Dieting)

How many times have you felt pressure from your doctor, your loved ones, yourself, and even all of society to lose weight? It’s something many of us feel, and if your BMI is over 30, chances are it’s pretty constant. You’ve probably tried your fair share of diets, which can lead to yo-yo dieting, a never-ending cycle of weight loss and weight gain that can be far more harmful than you realize. Fortunately, there may be a way out. Research suggests that focusing on 21 minutes of daily exercise instead of weight loss is a much healthier way to live. 

Weight loss is currently the primary focus of obesity treatment, but a recent review published in Cell Press challenges that approach. According to the review, obesity prevalence has doubled in more than 70 countries since 1980. At the same time, weight loss attempts have increased as well. Such attempts have not reduced levels of obesity in America or the health risks associated with obesity. They may also cause health risks of their own. In other words, the study authors argue, constantly trying new diet plans may not be the best solution.

To confirm this theory, the research team conducted multiple in-depth reviews of weight loss and exercise studies. They focused on the relationship between intentional weight loss and the risk of death caused by cardiovascular issues. They also analyzed the link between physical activity and mortality risk. Ultimately, they determined that exercise is consistently better at reducing the risks associated with obesity than intentional weight loss. 

“Most of the risks associated with obesity probably are due to low fitness levels and lack of physical activity, and these can be corrected,” says study co-author Glenn Gaesser, a Professor in the College of Health Solutions at Arizona State University. “Diet culture can be very harmful. Whether it’s more harmful than obesity is probably debatable. But in general, because we have a diet mentality that kind of worships thinness – and this has been going on for decades – I think in large part the overall diet culture and the harm it may do probably exceeds the risks associated with obesity.”  

The Dangers of Weight Loss Cycling 

You may think that trying out a new diet every so often will prevent a plateau and help you lose more weight. However, the opposite is true. The American Psychological Association points out that with every diet, you are more likely to lose some weight initially but then regain it over time. You may even gain more weight. The cycle goes something like this:  

• You notice or your doctor tells you that you are overweight. 
• You decide you want to lose weight.  
• You try different weight-loss strategies. 
• You don’t reach your weight-loss goal, or you are unable to maintain the weight loss.  
• You feel frustrated and don’t stick to your strategy. 
• You regain the weight you lost and perhaps even more.  
• You’re back to where you started. 

Constantly dieting may not only cause you to gain more weight in the end, but also lead to a slew of health problems.  

“A lot of the diseases associated with yo-yo dieting are similar to the diseases that are linked to obesity,” says study co-author Siddhartha Angadi, an Assistant Professor of Education in the Department of Kinesiology at the University of Virginia. “Yo-yo dieting has been shown to increase your risk of cardiovascular disease. Yo-yo dieting has been shown to increase your risk of certain cancers. It has been shown to increase levels of inflammation. This is very much a case of where the quote unquote cure – telling people to lose weight – is worse or causes the same problem as the condition that you’re trying to cure.”    

In their paper, Angadi and Gaesser point to research from 2019 which showed that weight cycling, or yo-yo dieting, increases the risk of cardiovascular-related death by 36 percent. Another analysis from 2019 found that weight cycling increases the risk of death in general by 45 percent.  

Why does dieting cause the body so much harm? “When you weight cycle, you get these large fluctuations of blood pressure and large fluctuations in heart rate,” Angadi explains. “That places an increased load on your cardiovascular system.” Weight cycling may also cause large fluctuations in blood glucose levels, blood lipid levels, and insulin.  

What’s more, genetics play a huge role in a person’s weight. “The heritability of weight is about the same as that of height,” Gaesser points out. “It would make no sense to tell a short person who doesn’t like being short, ‘Just grow taller. Just stretch yourself out.’”  

“It’s kind of problematic that people view obesity as a behavior when it’s not,” Angadi adds. “It’s a physical characteristic that has a strong genetic basis. And that’s one of the major reasons why it’s treated as a disease, not as a personality flaw.”  

Why You Should Ignore BMI and Just Exercise 

Though body mass index (BMI) has been used for decades to measure our health, research suggests that it is an inaccurate health marker. The National Heart, Lung, and Blood Institute states that BMI is a measure of body fat based on height and weight. However, study authors Angadi and Gaesser argue that it tells us nothing about fat content and location.  

“BMI is a terrible measure or indicator of your health,” Gaesser says. “Body mass index does not tell us anything about how much fat we have or where it’s located. And even more important, the body mass index charts don’t tell us anything about our behaviors.” 

“If you use BMI to tell you that you’re fine, then there’s a lot of information that’s really being missed,” Angadi adds. “So that’s really given rise to the misunderstanding of what it means to be metabolically healthy. To be metabolically healthy, you really need to look at these markers of cardiovascular risk that meaningfully predict your future risk of cardiovascular all-cause mortality. And the goal should be to try and normalize those.” 

In other words, focusing on your weight and where you are on the BMI scale tells you very little about your health. Measuring other markers, like your blood sugar levels and cholesterol levels, will tell you much more. As shown by Angadi and Gaesser’s research, one of the best ways to get those levels down to a healthy range is to exercise.  

So, what types of exercise will help you get healthy, and how long should you spend exercising each week? Gaesser recommends following the current public health guidelines, which suggest 150 minutes of moderate intensity activity, like brisk walking, each week. “At first glance that may sound a little bit challenging. 150 minutes is two and a half hours,” he says. “But if you divide that by seven days a week, it’s only 21 minutes a day.”  

If you don’t have much time, you can split those 21 minutes into a few smaller bursts of exercise. And if you simply can’t get in 150 minutes each week, some is better than nothing. “Exercise is really good medicine,” Angadi says. “And what [that] means is that anybody can be active and anybody can improve their health by exercising.”  

“Fit and healthy bodies come in all shapes and sizes,” Gaesser concluded.