Weight Regain May Not Fully Diminish Benefits of Weight Loss on Cardiometabolic Health

For persons with overweight or obesity, participating in an intensive behavioral weight management program (BWMP) was associated with a decrease in risk factors for cardiometabolic disease for at least 5 years after program completion, despite some weight regain over that period.

The finding, from investigators at the University of Oxford, is the result of a systematic literature review and meta-analysis of more than 120 randomized controlled trials evaluating BWMP of varying intensities and the legacy effect of weight change on risk factors for cardiovascular disease (CVD) and type 2 diabetes (T2D). The results were published online March 28, 2023, in Circulation: Cardiovascular Quality and Outcomes.

“Many doctors and patients recognize that weight loss is often followed by weight regain, and they fear that this renders an attempt to lose weight pointless,” said senior investigator Susan A. Jebb, PhD, a professor of diet and population health at the University of Oxford in the United Kingdom, in a news release. “This concept has become a barrier to offering support to people to lose weight. For people with overweight or obesity issues, losing weight is an effective way to reduce the risk of Type 2 diabetes and cardiovascular disease.”

Current data sparse

Study authors note that while the evidence for the beneficial effects of weight loss during treatment programs on markers of cardiometabolic health is robust, there is little research on the impact of the weight regain trajectory so commonly seen on those markers. They add, in fact, that some observational studies suggest the weight change pattern may increase cardiovascular risk, but data from randomized controlled trials are rare. Jebb and colleagues also note that individual trials lack the power to assess the impact of weight regain on cardiometabolic risk and disease.

To begin closing these gaps in knowledge, the investigators conducted a wide-reaching systematic literature review and meta-analysis of trials that evaluated weight change after the end of a BWMP to assess whether weight regain after completion was associated with change in risk factors for CVD and T2D.

The search for randomized controlled trials was conducted in 2018 and comprised clinical trial registries and 11 electronic databases. Trials included evaluated BWMP in adults with overweight or obesity and reported cardiometabolic outcomes at 1-year or beyond and after program end. Within trials comparators had to be another BWMP, a less intense intervention or no intervention at all.

The 124 trials chosen for analysis included more than 50 000 participants with a median age of 51 years and median baseline BMI of 33 kg/m². Median follow up time was 28 (range, 11-360) months after program end. Analysis found the average weight loss across studies was 5-10 lbs and average weight regain per year, 0.26 to 0.7 lbs.

Analysis of bias found that 52% of trials were at unclear risk of bias, primarily because they did not fully report randomization procedures, 27% were at low risk, and 22% were at high risk.

FINDINGS

The incidence of CVD was examined in 8 study arms (7889 participants) and of T2D in 15 study arms (4202 participants) with “imprecise evidence of a lower incidence for at least 5 years,” according to study authors. Very few of these studies followed participants for more than 5 years, according to the study, and so persistence of any benefits needs to be investigated further, according to Jebb.

Jebb and colleagues report that overall, risk factors for CVD and T2D were lower among study participants who lost weight in an intensive BWMP vs those in less intensive programs or no intervention at all; the decreases in these measures were durable for at least 5 years after completion of the BWMP, although improvements diminished with weight gain.

The researcher’s analysis of specific risk factors for CVD and T2D at 1 and 5 years after BWMP end, found:

• total cholesterol/HDL ratio was 1.5 points lower at both times (82 studies; 19,003 participants)
• HbA1c was 0.38 percentage points lower at both times (94 studies; 28,083 participants)
• systolic blood pressure was 1.5 mm mercury and 0.4 mm lower (84 studies; 30,836 participants) at the 1- and 5-year time points

When they removed trials considered to be at high risk of bias from the analysis, investigators observed no meaningful change in the results, according to the study.

“…BWMPs appear to lead to a temporary reduction in exposure to cardiometabolic risk factors that may last several, perhaps 5, years. Evidence suggests that these temporary reductions in risk factors are likely to lead to lifetime benefits of reduced incidence of CVD,” the authors conclude.

Reference: Hartmann-Boyce J, Theodoulou A, Oke JL, et al. Long-term effects of weight regain following behavioral weight management programs on cardiometabolic disease incidence and risk: systematic review and meta-analysis. Circ Cardiovasc Qual Outcomes. Published online March 28, 2023. doi:10.1161/CIRCOUTCOMES.122.009348