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Gastric bypass surgery may reduce cardiovascular disease risk regardless of weight loss
Last reviewed: 02.07.2025
In a recent study published in JAMA Surgery, researchers examined whether Roux-en-Y gastric bypass (RYGB) reduces cardiovascular risks independent of calorie restriction and weight loss.
Bariatric surgery is more effective than nonsurgical treatments in reducing body weight and cardiovascular disease risk in overweight people. RYGB also reduces cardiovascular risk, morbidity, and mortality, although the exact mechanisms remain unclear.
In this uncontrolled study, researchers assessed changes in cardiovascular risk over six weeks in obese people who either underwent a very low-calorie diet (VLED, less than 800 kcal/day) or Roux-en-Y gastric bypass (RYGB) with associated calorie restriction and weight loss.
A study conducted in Norway included adults with severe obesity planning to undergo VLED or RYGB. Participants were randomly assigned to undergo three weeks of low-calorie diet (LED, less than 1200 kcal/day) before six weeks of VLED (n=37) or six weeks of VLED after RYGB (n=41).
Measurements included body mass index (BMI), total body fat percentage, waist and hip circumference, insulin sensitivity, fasting glucose, blood lipids, blood pressure, and cardiometabolic biomarkers.
Of the 78 participants, the mean age was 48 years, 65% (n=51) were women, and 99% were white. Primary atherogenic lipids such as LDL, non-HDL, apolipoprotein B, and lipoprotein(a) were reduced after RYGB compared with VLED, despite comparable fat loss. The RYGB group lost more weight than the VLED group, with a mean difference of 2.3 kg.
Changes in glycemic control and blood pressure were similar in both groups.
The study found that RYGB may reduce cardiovascular risk independent of weight loss, particularly in severely obese individuals. The RYGB group showed a reduction in primary atherogenic lipids six weeks after surgery, which was not seen in the VLED group despite comparable fat loss.
These results highlight the importance of RYGB as an effective intervention to reduce cardiovascular risks in individuals with severe obesity, which requires further research to understand the long-term effects and mechanisms.