It can be downright discouraging to work hard to lose 10 pounds, only to regain a few later.
But don't be downhearted -- a new evidence review says the important heart health benefits of weight loss are sustained even if some of the weight comes back.
People who drop some pounds still have lower blood pressure and better cholesterol and blood sugar numbers even if they regain a little, British researchers reported March 28 in the journal Circulation: Cardiovascular Quality and Outcomes.
“It should serve as encouragement for people to try to lose weight, and do so in the most effective way by joining a behavioral weight loss program,” said senior researcher Paul Aveyard, a professor of behavioral medicine at the University of Oxford. “Even if weight is regained, which most people do, the health benefits persist.”
For this review, Aveyard's team analyzed the combined results of 124 weight loss clinical trials involving more than 50,000 people and with an average follow-up of more than two years.
The participants' average age was 51, and their average body mass index (BMI) was 33, which is considered obese. BMI is an estimate of body fat based on height and weight.
On average, people assigned to a weight loss program shed 5 to 10 pounds as a result of the initial experiment, which typically lasted around seven months.
Behavioral weight loss programs help people lose weight by encouraging lifestyle changes such as eating healthy foods or stepping up physical activity.
“[The programs] help people clarify their goals and set goals and they monitor how well people are doing,” Aveyard said. “They give them support to think through their lives and how they can follow the dietary restrictions and boost their physical activity. They boost motivation, and also help people to feel understood and better about themselves and their weight.”
During follow-up, participants regained an average 0.26 to 0.7 pounds a year, a slow drip of weight gain that experts say isn't unusual.
“It's very hard to maintain lost weight,” Aveyard said. “The reasons a person gained weight have not gone away after weight loss, so most people do regain weight.”
However, people who participated in a weight loss program still maintained lower blood pressure, cholesterol and blood sugar numbers for at least five years after the program ended, compared to those not asked to lose weight, the evidence review found.
“Blood pressure was lower, cholesterol lower, and blood glucose was lower for at least five years for those offered the weight management program,” Aveyard said. “It looked like the onset of disease -- heart disease and diabetes -- remained lower, but too few studies had measured these diseases to be sure.”
The health benefits did tend to diminish as a person regained more weight, noted nutrition expert Christopher Gardner, a professor with the Stanford Prevention Research Center in Stanford, Calif.
“The ones who regained the most weight had the greatest diminishment of the benefit, but it didn't go the other way. It didn't go into an adverse thing” where their weight regain took a toll on heart risk factors, said Gardner, who also serves as chair of the American Heart Association's Nutrition Committee.
“It was better to have lost and regained," he said. "For some portion of your life, your metabolism was cleared up and that probably has a cardiovascular and a diabetes benefit in the long run.”
This is an important paper because the weight loss clinical trials included in the evidence review featured long-term follow-up, something that doesn't usually happen, Gardner said.
“This is really such a huge missing gap,” he said. “The critical question is: What does happen five, 10 years down the road” after a person drops some excess weight.
So why did the heart health benefits remain even after weight regain?
The clinical trials weren't designed to examine the reasons behind the results, but experts offered a couple of likely theories.
Losing weight might cause a metabolic reset that persists even if some weight comes back, said Dr. Francisco Lopez-Jimenez, chair of preventive cardiology at the Mayo Clinic in Rochester, Minn.
“Most of the benefits when losing weight actually rely on the on the initial weight loss,” he said. “We know that losing 5% of body weight prevents diabetes big time, like 70% of the risk for diabetes is cut.”
A lifestyle weight loss program also tends to decrease the belly fat that collects around organs, Lopez-Jimenez said. That fat puts pressure on the organs, increasing inflammation and doing systemic harm to the body.
“Many times patients start losing weight and the very first fat they burn is the abdominal fat, the fat that is mixed with the guts, what we call visceral fat,” he said. “That is actually the fat that causes most of the damage, so it makes sense that when people lose just a few pounds, you can see a significant metabolic benefit.”
Gardner agreed. “You're remodeling your body, the fat stores in your body, and that has an important metabolic effect,” he said.
Folks also need to keep in mind that the bathroom scale lies when it comes to how much body fat you've dropped during a weight loss program, Lopez-Jimenez said.
Lean muscle weighs more than body fat, so someone who exercises along with dieting might witness a modest overall weight loss that's actually disguising a much more successful drop in their fat stores.
“People might lose a pound at the end of the program or 2 pounds at the end of the program, and that sounds very disappointing,” Lopez-Jimenez said. “But we have shown that people actually gain muscle mass, and therefore, the difference in weight might actually not represent the actual amount of fat they burned.”
There are other important questions about weight loss this evidence review didn't address, including the effects of continually dropping and regaining pounds again and again, Gardner said.
“I think that would be relevant for some people because I think that kind of cycling is potentially messing up your metabolism,” he said.
Gardner also is concerned about the possible effects of massive weight loss and regain. He noted that people who competed in "The Biggest Loser" TV show would lose 100 pounds only to regain it later with lasting effects on their metabolism.
“They didn't address that here, but what they did address is what's most realistic for a lot of people, the effects of losing 5 or 10 pounds,” Gardner said.
Gardner and Lopez-Jimenez said the message from this evidence review is clear and important.
“I think people need to be happy whenever they are able to lose a few pounds because the benefit is not trivial. It's significant,” Lopez-Jimenez said. “And many times that initial benefit, that initial weight loss actually helps patients to keep the momentum. Once they recognize the benefit of that initial modest weight loss, taking the next step in terms of exercise and diet is easier because they just keep the momentum going.”
The Mayo Clinic has more about choosing an effective weight-loss diet. The American Heart Association has more on Life's Essential 8 factors for maintaining heart health.
SOURCES: Paul Aveyard, PhD, professor, behavioral medicine, University of Oxford, U.K.; Christopher Gardner, PhD, research professor, medicine, Stanford Prevention Research Center, Stanford, Calif.; Francisco Lopez-Jimenez, MD, chair, preventive cardiology, Mayo Clinic, Rochester, Minn.; Circulation: Cardiovascular Quality and Outcomes, March 28, 2023