A healthy body requires a minimum amount of fat for proper functioning of the hormonal, reproductive, and immune systems, as thermal insulation, as shock absorption for sensitive areas, and as energy for future use; however, the accumulation of too much storage fat can impair movement, flexibility, and alter the appearance of the body.

[12][13] The specific conclusions appear to depend on what other factors are controlled for,[11] and Flegal has accordingly alleged that the findings from the 2016 review are driven by bias toward preconceived opinions.

Dietitians generally recommend eating several balanced meals dispersed through the day, with a combination of progressive, primarily aerobic, physical exercise.

In fact, some research found benefits from physical activity, diet and behaviour changes on BMI in children from 12 to 17 years old.

[20] Considering that most of the treatment strategies are directed to change lifestyle-related behaviours of individuals (namely in dietary and physical activity), the transtheoretical model (TTM) has been used as a framework to design weight management interventions.

A systematic review assessed the effectiveness of dietary and physical activity interventions based on the TTM in producing sustainable (one year or longer) weight loss in overweight and obese adults.

The included studies did not allow to produce conclusive evidence about the impact of the use of this model combined with these interventions on sustainable weight loss.

[22] According to the National Health and Nutrition Examination Survey (NHANES), an estimated 71.6% of the United States' adult population aged 20 and over is considered either overweight or obese, and this percentage has increased over the last four decades.