Obesity

The impact of 3 different dietary interventions on overweight or obese adults: A network meta-analysis

As obesity rates and related chronic disease continue to rise, identifying effective dietary strategies is crucial. Over the past several years research has shifted toward evaluating whole dietary patterns rather than individual nutrients to understand their comprehensive health impacts.

Researchers recently analyzed results from multiple randomized controlled trials to compare the effectiveness of ketogenic, low-fat, and Mediterranean diets on body weight, BMI, and waist circumference, aiming to determine the most effective approach for managing obesity.

Seventeen studies met the inclusion criteria, representing diverse locations including the United States, Greece, and Australia. The analysis covered interventions assessing body weight (BW), body mass index (BMI), and waist circumference (WC) using a network meta-analysis model. To ensure reliability, the study controlled for potential bias by evaluating the risk in the included trials and analyzing consistency across the data.

Note: With the exception of three ad libitum low-fat diet trials, all other interventions were calorie-restricted, including the ketogenic diet. However, the degree of restriction varied from very-low-calorie (700-800 calories per day) to mildly hypocaloric (up to 1850 calories per day).

Results:

• Ketogenic diet: Most effective in reducing BW, BMI, and WC, showing statistically significant results compared to all other diets. Ranked highest in probability for effectiveness across BW, BMI, and WC measurements.
• Low-fat diet: Second most effective overall, showing significant improvements in BW and BMI compared to low-calorie and Mediterranean diets.
• Mediterranean diet: Ranked third most effective for BW, BMI, and WC outcomes; however, noted to be a beneficial dietary approach for overall health despite its lower weight-reduction ranking.

This meta-analysis identified the ketogenic diet as the most consistently effective approach for reductions in weight and waist circumference. Limitations include a moderate study quality, varying lengths of study duration, and geographical diversity, which may introduce variability.