Meal replacement trumps food-based diet for improving CV risk factors in obese adults

In the secondary and exploratory analyses of the OPTIWIN trial, meal replacement (MR) outdid a food-based (FB) regimen in improving cardiometabolic risk in adults with obesity.

“In the setting of an intensive behavioural intervention for obesity, the use of a total MR dietary intervention led to greater improvements in cardiovascular (CV) risk factors compared with a proven FB diet,” said Dr Jamy Ard from the Wake Forest University School of Medicine, Winston-Salem, North Carolina, US, at ADA 2023.

At week 26, there was a greater reduction in systolic blood pressure (SBP) with MR vs the FB diet (least squares mean [LSM], –4.9 vs –1.4 mm Hg; p=0.006). “However, there was a slight tick back up by week 52. The difference was no longer significant, but SBP was still reduced for both groups,” Ard noted.

Diastolic BP (DBP) followed a similar pattern (LSM, –2.8 vs –0.3 mm Hg; p=0.005), as did mean arterial pressure (MAP; LSM, –3.5 vs –0.6 mm Hg; p=0.002) at week 26. Again, these effects diminished by week 52.

There were also greater improvements in total cholesterol (LSM, –6.5 vs –1.8 mg/dL; p=0.043), LDL-C* (LSM, –5.6 vs –0.6 mg/dL; p=0.018), HDL-C* (LSM, 4.7 vs 1.4 mg/dL; p<0.0001), and triglycerides (LSM, –32.7 vs –4.7 mg/dL; p<0.0001) with MR vs the FB diet at week 26. Except for total cholesterol, statistical significance was sustained for the latter three lipid parameters at week 52.

Week 26 also saw a drop in ASCVD** score with MR, as opposed to an increase with the FB diet (LSM, –0.6 percent vs 0.1 percent; p=0.003). Individuals aged ≥60 years (p=0.02), males (p=0.007), and those with a BP of ≥130 mm Hg (p=0.007) had greater reductions in ASCVD risk as a result of the MR strategy.

Key goals: Drop weight, alleviate CV risk

“The key goals of obesity management are not only to reduce body weight, but also to mitigate cardiometabolic complications,” stressed Ard. MR is a strategy that can help in achieving greater weight loss and is supported by several*** societies. “MR also reduces choices and makes life simple … It’s nutritionally controlled and portion-controlled.”

However, the magnitude of its effect on CVD risk is not fully understood. Ard and team thus set out to compare the efficacy of MRs against a low-calorie FB diet in terms of reducing CVD risk. They evaluated 273 participants (mean age 47 years, ~80 percent female). Mean BMI ranged between 38 and 39 kg/m². The study had two phases: reduction (weeks 0–26) and maintenance (weeks 26–52).

MR group participants were to consume five MRs daily (800 kcal) from week 0 to 12. Food was gradually reintroduced from week 13 to 26. Conversely, the FB diet was cut by 500–750 kcal below the estimated total energy expenditure (fat 25–30 percent of total calories). Calories were gradually increased to achieve weight stability during the maintenance phase (those on MR were to consume 1–2 MRs daily).

“Once people stopped being in a negative energy balance, they tended to have sustained improvement in some parameters. We saw significant reductions in SBP, DBP, and MAP with total or partial use of MRs vs FB programme,” Ard said. “However, these were not sustained over 52 weeks. Some things like BP did tend to go back up slightly to baseline in both groups.”

“In general, following transition from a total MR programme to a maintenance phase with partial MR for an additional 26 weeks, the benefits on CV risk factors were sustained for lipid parameters, but less pronounced for BP and vascular parameters. The reduction in ASCVD remained significant,” Ard concluded.