"The obvious reason for obesity is eating too much sugar and refined carbohydrates. But statistically how much does this add to the risk of obesity?
A 2019 meta-analysis of different food intake studies and weight gain showed that consumption of refined grains increased the relative risk of obesity by 5% and the consumption of sugar-sweetened beverages increased the relative risk of obesity by 10%. Eating more legumes, fruit, and fish all tilted the scales in the other direction, reducing the risk of obesity by 5-15%. The study concluded, “The dose-response meta-analytical findings provided very low to low quality of evidence that certain food groups have an impact on different measurements of adiposity risk.”"
Food Groups and Risk of Overweight, Obesity, and Weight Gain: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies