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Healthy Weight: Results from Studies in Adults

A large number of studies have investigated the effect of dairy consumption on adult body weight and composition. The evidence to date indicates that dairy consumption has a favourable impact and may help adults in weight management.

The Evidence

In a 2016 meta-analysis of 27 randomized controlled trials, the authors concluded that dairy intake enhanced body weight and composition changes during energy restriction among 1,278 adults aged ≤50 years. Specifically, the participants in the intervention group consumed 2 to 4 servings of dairy products or 20 to 84 g of whey protein per day over 16 weeks. Compared to the control group, those in the dairy group:¹

• Had a greater reduction in body weight (-1.2 kg) and body fat mass (-1.5 kg);
• Had a ~75% smaller loss of lean mass.

In another meta-analysis of randomized controlled trials, Benatar et al. evaluated the association between increased dairy product intake and cardiometabolic risk factors. The analysis consisted of 20 studies with a total of 1,677 healthy adults, who were randomized to increased dairy intake (3.6 servings added to a regular diet, without controlling for energy intake). Dairy products were classified as low-fat dairy (<1% fat) and whole-fat dairy (full-fat milk, cheese, butter, cream and ice cream).²

• Although a small increase in weight was observed with both low- and whole-fat dairy, there were no significant changes in waist circumference.

A meta-analysis of 24 prospective cohort studies was conducted to assess the relationship between dairy intake and changes in anthropometric factors, such as body weight, waist circumference and abdominal obesity, among adults.³

• Total dairy intake was associated with decreased abdominal obesity and no weight gain;
• Whole-fat dairy was associated with reduced adiposity;
• Higher yogurt intake was associated with decreased body weight and waist circumference, as well as with a risk reduction in abdominal obesity and being overweight.

A 2016 systematic review of randomized controlled studies and observational studies investigated the effect of yogurt consumption on weight-related outcomes, including body weight, BMI, body fat, lean body mass and waist circumference.⁴

• In observational studies, yogurt consumption was associated with lower body weight, lower BMI, lower body fat and smaller waist circumference;
• Results from randomized controlled trials also suggested weight reduction effects;
• The authors concluded that consuming yogurt daily may facilitate loss of body fat.

Conclusion

There is strong evidence that dairy consumption, particularly as part of an energy-restricted diet, is beneficial to the achievement of healthy weight and body composition in adults. Regular/whole-fat dairy does not appear to be associated with unfavourable weight-related outcomes and may be associated with reduced adiposity.

Some types of dairy products, such as yogurt, appear to be inversely associated with weight gain. Additional research is needed to clarify the role of different types of dairy products in weight loss and maintenance.

More studies are also needed to confirm the potential differential role of low- versus regular/whole-fat dairy products.

Finally, more studies are also needed to investigate the long-term effects of dairy consumption on body weight and composition.

Keywords: healthy weight