Generated Summary
The article discusses a phase 2 trial that investigated the effects of modest calorie reduction on cardiometabolic health in healthy, nonobese adults. The study, published in The Lancet Diabetes & Endocrinology, involved 218 participants aged 21 to 50 years who were randomly assigned to either a calorie-cutting group or a control group. The calorie-cutting group aimed to reduce their daily intake by 25%, while the control group was instructed to eat what they liked. Researchers measured changes in weight, fat mass, and various cardiometabolic risk factors, including blood pressure, plasma lipids, high-sensitivity C-reactive protein (hs-CRP), metabolic syndrome score, and fasting insulin, glucose, and insulin resistance over a 2-year period. The study aimed to determine the impact of calorie restriction on improving cardiometabolic health.
Key Findings & Statistics
- The study found that the dropout rate was 18% in the calorie-restriction group and 5% in the control group.
- The calorie-cutting group managed to trim caloric intake about 12% on average, compared with about 1% in the control group.
- This corresponded to 279 fewer calories a day at the end of the first year and 216 fewer calories at the end of the second year.
- On average, the calorie-cutting group lost about 16.5 lb—10% of their body weight—by the end of the study, and 71% of it was fat mass.
- Meanwhile, the control group gained about a quarter of a pound.
- All cardiometabolic risk factor values improved in the calorie-restriction group but not in the control group.
- Even if everyone in the calorie-restriction group had been able to reduce their intake by 25%, it wouldn’t have improved their cardiometabolic risk factors much more than cutting caloric intake by 12% did.
Other Important Findings
- The article mentions that animal and observational human studies have suggested that cutting empty calories might protect against cardiovascular disease. A study involving rhesus monkeys placed on a restricted-calorie diet at a young age had half the incidence of cardiovascular disease compared to those consuming a typical diet.
- An observational study showed that people who chose to restrict their calorie intake for an average of 6 years had more favorable cardiometabolic risk factors.
- For people with normal baseline cardiometabolic risk status, 2 years of caloric restriction led to trimmer waistlines, higher high-density lipoprotein cholesterol, and lower blood pressure, among other improvements.
Limitations Noted in the Document
- The study’s primary limitation is the short-term nature of the intervention (2 years). Longer-term studies would be needed to assess the durability of the observed benefits and the potential for a reduced risk of cardiovascular disease.
- The study focused on a specific population: healthy, nonobese adults aged 21 to 50. The findings may not be generalizable to older adults or individuals with existing health conditions.
- The study did not fully explore the mechanisms by which calorie restriction improved cardiometabolic risk factors. Further research could investigate the specific biological pathways involved.
- The article notes that even if everyone in the calorie-restriction group had been able to reduce their intake by 25%, the improvement in cardiometabolic risk factors would not have been significantly greater than the observed 12% reduction. This suggests that the degree of caloric restriction is more critical than the targeted percentage.
Conclusion
The study suggests that modest calorie restriction can improve cardiometabolic health in healthy adults. The results align with previous research indicating that even healthy individuals can benefit from calorie restriction. The key takeaway is that reducing daily calorie intake, equivalent to, for instance, skipping a slice of pizza or a couple of cans of sugary soda, can lead to improvements in cardiometabolic risk factors. The authors emphasize that these benefits cannot be explained by weight loss alone. William Kraus, MD, a Duke University preventive cardiologist, suggests that the public health benefit could be substantial if everyone made a similar sacrifice. Furthermore, it’s probably never too late to try to improve cardiometabolic risk factors, especially considering that they tend to worsen with age. Moreover, the study notes that the benefits of calorie restriction may persist and result in a lower risk of cardiovascular disease in the long run. This is a key area for future research. As Kraus said, “It’s not hard to do. It just takes a little intention and discipline.”