Losing weight — even if some pounds are gained back — may help your heart over the long term, according to a study published Tuesday in the journal Circulation: Cardiovascular Quality and Outcomes.
The findings may be welcome news to those who have found it difficult to keep weight off and feared the risks thought to be associated with gaining weight back.
In the new study, researchers analyzed data from 124 clinical trials with a total of more than 50,000 participants. They found that risk factors for heart disease and Type 2 diabetes decreased for people who lost weight through intensive behavioral programs. The diminished risk persisted for years after they were done with the programs, even if some, but not all, of the weight came back.
“The whole time your weight is less than it would otherwise have been, your risk factors for heart disease are lower than they would have been,” co-author Susan Jebb, a professor of diet and population health at the University of Oxford in the United Kingdom, said in an email.
The new analysis included trials that looked at the impact of behavioral weight management programs — those that provided, for example, counseling, coaching and education — on heart disease risk factors and had follow-up periods of at least one year. The median follow-up for the trials was 28 months.
The included studies compared people who participated in such intensive weight loss programs to those who followed less intensive programs or no program at all. The studies in the analysis included diet or exercise interventions or both, partial or total meal replacement, intermittent fasting or financial incentives contingent on weight loss.
The researchers found that the average weight loss across the included studies was 5 to 10 pounds, while the average weight regain was 0.26 pounds to 0.7 pounds a year. The average age of the participants at the outset was 51, and their average body mass index was 33, meaning they were obese.
Compared to the control groups, those in intensive programs improved in several heart disease risk factors:
- Systolic blood pressure, on average, was 1.5 points lower one year later and still 0.4 points lower five years later. (Systolic pressure is the top number in a blood pressure reading.)
- HbA1c, an indicator of a person’s blood sugar over the previous three months, dropped with weight loss and, while it began to rise again with weight regain, still remained better compared to the control group at one and five years after the end of the studies.
- The ratio of total cholesterol to HDL cholesterol, an indicator of LDL cholesterol levels, improved with weight loss, although those improvements were smaller as people regained weight.
Jebb acknowledged that the improvements with weight loss do begin to reverse as a person puts weight back on, but “at least you have reduced the metabolic burden on your body for a period of time,” adding, “That can be enough to delay the onset of diabetes, for example, which has a big benefit for your heart.”
The overall findings suggested that the risk of developing diabetes or having a heart attack was also reduced, but there is less information about that, “because most trials don’t follow up for a long time,” Jebb said.
A subset of the studies that did look at the risk of being diagnosed with heart disease or Type 2 diabetes found that people in intensive programs had lower risk compared to those in the control groups. And the risk remained lower even after weight gain.
Dr. Sean Heffron, a preventive cardiologist and an assistant professor of medicine at NYU Langone and the NYU Center for the Prevention of Cardiovascular Disease, agreed that what is still needed is information about the long-term impact on “the outcomes we really care about: heart attack, stroke and death.”
“The people in this study were relatively young, and it takes a long time for people to die” from heart disease, he said.
Still, the findings “support what we see clinically with a number of cardiovascular risk factors,” said Heffron, who was not involved with the new research. “They are quite responsive to weight loss, even when the amounts are not large.”
Dr. Matthew Tomey, an interventional cardiologist and an assistant professor of medicine and cardiology at the Icahn School of Medicine at Mount Sinai in New York, compared episodes of weight loss to money going into a bank account.
Weight loss at any time in life leads to gains through improvements in risk factors, and that “is a health promotion investment that you can reap rewards from,” said Tomey, who was not involved with the research. “The reality is that it can be very challenging to both achieve and sustain a target body weight. That doesn’t mean one should abandon the pursuit.”