Nutritional Pearls: Keeping the Weight Off Requires Less Exercise Than You Might Think
Answer: Improving diet and a moderate amount of exercise is beneficial. Significant health benefits can come from engaging in moderately vigorous exercise for at least 30 minutes per day, 5 days per week.
The Research: Those with overweight or clinical obesity will also reap significant health benefits from engaging in moderately vigorous exercise for at least 30 minutes per day, 5 days per week.
The role of at least moderate amounts of exercise in overall health is clear. Yet, despite the received weight-loss wisdom of "eat less and exercise more," it is not nearly as clear whether exercise alone is as effective for initial weight loss as it is for helping maintain weight loss or preventing regaining lost weight.
A team at the University of Kansas designed a randomized, controlled trial to assess the effect of specific amounts of exercise on the maintenance of weight loss.1 Initially the research included 298 men and women who participated in an intensive weight-loss program that included weekly counseling, increased exercise of up to 20 minutes per day for 5 days per week, and a reduced-calorie diet of provided meals and shakes to help them lose a goal of at least 5% of their initial body weight.
A total 235 men and women achieved their goal of at least 5% of their initial weight lost and moved on to the second phase of the trial. In addition to continued behavioral and dietary counseling, the participants were randomly assigned to 1 of 3 levels of exercise that ramped up within the first 2 months of the trial to 150 minutes per week, 225 minutes per week, or 300 minutes per week––all moderate-intensity exercise.
Over the following year, the participants engaged in some professionally monitored exercise, but most exercise was self-reported. Similarly, their dietary intake and body weight were also self-reported. The participants also filled out 3-day food records every 3 months throughout the maintenance period to help the researchers assess their adherence to their lower-calorie lifestyle.
About 75% of the 235 participants completed the year's trial.
The Results: On the one hand, the results might be disappointing: none of the 3 exercise groups met their exercise goals. On average, those who were assigned to the 150 minutes of exercise completed about 129 minutes of exercise; those assigned to 225 minutes of exercise per week only completed 153 minutes of exercise; and those assigned to the highest level of exercise—300 minutes per week––only completed 179 minutes per week.
As the researchers noted, "No significant between-group differences in weight regain across 12 months were evident": all 3 exercise groups regained about the same amount of weight. More importantly, however, 88% of those who completed the 12-month trial had lost at least 5% of their starting body weight and kept it off.
The researchers had expected that those who exercised for more minutes per week would avoid regaining more of their lost weight, but this did not happen. Although the majority of those in the 150 minutes per week group did not meet their exercise goal, they still kept off the lost weight at about the same rate as those who exercised far more.
What This Means For You
1. Losing a significant amount of weight by reducing caloric intake (and/or burning more calories) without surgical or other clinical assistance is possible, but it is far more difficult to keep that significant amount of weight off for the long term.
2. We know that regardless of an individual's starting weight, losing even a modest amount of weight––as little as 5% of their starting weight––and keeping it off has significant positive effects on their risk of metabolic disorders and chronic conditions such as diabetes, cancer, and heart disease. Similarly, a person who is clinically obese does not have to become a person who is clinically normal weight to benefit significantly from improving their diet, even if they do not lose a kilogram.
3. The benefits of a moderate amount of exercise are undeniable but, again, are not solely contingent on weight loss. Those who are overweight or clinically obese will also reap significant health benefits from engaging in moderately vigorous exercise for at least 30 minutes per day, 5 days per week ("moderately vigorous" means getting your heart rate up so that it is a little difficult to carry on a conversation while exercising). Do whatever you enjoy doing, from walking to chair aerobics, to dance, or weightlifting, but get moving.
- Washburn RA, Szabo-Reed AN, Gorczyca AM, et al. A randomized trial evaluating exercise for the prevention of weight regain. Obesity (Silver Spring). 2021;29(1):62-70. https://doi.org/10.1002/oby.23022