By Clarissa Brincat — Fact checked by Jill Seladi-Schulman, Ph.D.
In the United States, nearly 1 in 3 adults (30.7%) are overweight, and more than 2 in 5 adults (42.4%) have obesity. The problem is not limited to America. Worldwide, nearly 2 in 5 adults (39%) were overweight in 2016, and more than 1 in 10 (13%) were obese.
These statistics are concerning because carrying excessive weight significantly increases a person’s risk of developing cardiovascular diseases (mainly heart disease and stroke), diabetes, musculoskeletal disorders (especially osteoarthritis), and some cancers.
To avoid these problems, programs have been designed to help people lose weight by changing their behavior related to diet, exercise, and lifestyle. Most of these behavioral weight management programs, or lifestyle modification programs as they are also known, are effective at helping people lose weight over a 12-month period.
Now, researchers at the University of Oxford want to understand whether behavioral weight management programs have long-term benefits beyond a year.
“Many people fear that weight loss attempts result in rapid weight regain and even over-shooting, so people might end up heavier than before the weight loss attempt. There was a fear that this would mean that weight loss did not benefit health long-term. We wanted to assess what really happens after weight loss attempts finish.”
– Prof. Paul Aveyard, Ph.D., professor of behavioral medicine at the University of Oxford and senior co-author
Prof. Aveyard and his coworkers reviewed randomized controlled trials from around the world to compare long-term health outcomes in people who participated in an intensive behavioral weight management program and others who received minimal or no weight loss support.
Their findings appear in Circulation: Cardiovascular Quality and Outcomes.
The goal of a behavioral weight management program is to help individuals achieve and maintain a healthy weight through long-term changes in their eating and physical activity behaviors.
These programs usually involve weekly one-on-one or group sessions with trained professionals such as dietitians, exercise specialists, or psychologists who provide education, counseling, and support to help participants adopt healthier habits and make sustainable changes in their daily lives.
One good example of these programs is the Diabetes Prevention Program (DPP) Lifestyle Change Program, which was developed by the Centers for Disease Control (CDC).
The researchers searched for randomized clinical trials that reported cardiovascular and metabolic (diabetes-related) outcomes in overweight or obese adults who participated in behavioral weight management programs.
The outcomes they focused on were:
- the occurrence of cardiovascular disease (CVD) and CVD-related death
- the occurrence of type 2 diabetes and hypertension
- changes in systolic blood pressure, serum cholesterol, blood glucose, and insulin measures.
Among 17,085 studies, they found only 124 randomized control trials which reported on at least one cardiometabolic outcome with at least 12 months of follow-up.
The researchers found clear evidence that, compared with lower-intensity behavioral weight management programs or no weight loss support, behavioral weight management programs resulted in lower systolic blood pressure, lower total cholesterol-to-good cholesterol ratio, and lower HbA1c (a measure of blood sugar levels over the previous 3 months).
These improved cardiovascular risk factors, except for glycemic control, persisted throughout the 5 years following the end of the program, although weight regains reduced these favorable effects over time.
The available data suggested that behavioral weight management programs also delayed the onset of heart disease and diabetes. Still, too few studies have measured these diseases to enable researchers to make high-certainty conclusions.
Dr. Lawrence J. Appel, the C. David Molina professor of medicine and director of the Welch Center for Prevention, Epidemiology and Clinical Research at Johns Hopkins University, who was not involved in the study, was surprised by the “legacy effect” of weight loss on blood pressure, cholesterol, and blood glucose.
“I was surprised because usually risk factors often track with weight changes,” Dr. Appel told MNT.
“The results provide reassurance that on average, there are long-term, albeit attenuated, benefits once a weight control program ends.”
– Dr. Appel
Dr. Naveed Sattar, Ph.D., professor and honorary consultant of cardiovascular & metabolic health at the University of Glasgow, who was not involved in the study, praised the research and told MNT that “the data do seem to suggest that the longer one loses weight for, the longer will be reductions in cardiovascular risk factors and so the greater the chances for a reduction in cardiovascular outcomes.”
However, Dr. Sattar noted that, in clinical trials to date, “changes in risk factors appear modest so any apparent cardiovascular benefits […] are likely rather modest with somewhat greater benefits in reducing risk of diabetes (as weight loss is more strongly linked to diabetes risk than it is to atherosclerosis)”
In 2022, the same research group published another study focusing on weight regain. They found that people who participated in behavioral weight management programs lost more weight (-2.8 kg) than those who received no support. It took an average of 5 years for the weight of people in the two groups to become similar.
This means that weight regain is slower than most people imagine. The reduced […] cardiovascular and metabolic disease [risk factors] persist because weight loss persists for longer on average than most people think- both last for at least five years. […] Even if weight is regained, which most people do, the health benefits persist.
– Prof. Aveyard
Prof. Aveyard went on to explain that: “[c]ardiovascular disease occurs because over time, high blood pressure, high cholesterol, and the high blood sugar gradually fur up our arteries [a process called atherosclerosis], leading to heart attack and stroke. If blood pressure, cholesterol, and blood sugar are lower, then the arteries fur up less, reducing the risk of these problems over a lifetime.”
Dr. Sattar noted that “the process of atherosclerosis […] takes years to develop, and to slow atherosclerosis likely will take a few years, especially if the risk factors are only modestly altered, as they are with modest weight loss.” He added that statins (cholesterol-lowering drugs) and blood pressure-lowering medications give faster clinical benefits than weight loss, but “weight loss gives other benefits that [these drugs] do not.”
“There is also evidence that big weight loss achieved by surgery lowers important cardiovascular outcomes, but that such benefits may be greater for heart failure and kidney outcomes, something not looked at in this paper,” Dr. Sattar said.
Trials with newer weight loss drugs such as semaglutide or tirzepatide may not definitively prove the cardiovascular benefits of weight loss as the drugs may directly affect such outcomes, Dr. Sattar told MNT.
“But they could go some way to convince cardiologists to consider weight loss more often in the management of their patients,” he noted.
This article originally appeared here and was republished with permission.