Weight Management with Dairy
Dietary calcium from dairy sources promotes healthy body weight
Dairy intake and calcium from dairy have desirable links with weight management. Protection against weight gain, lower total and central body fat, favourable metabolic profiles, effects on energy balance and appetite, and maintenance of lean body mass during weight loss efforts are part of the intricate interaction.
Obesity in South Africa
South Africa is not exempt from the international epidemic of obesity. According to the most recent South African Demographic and Health Survey (2003) and the National Food Consumption Survey of 20052 more than 50% of adult women are overweight or obese. The problem is also emerging amongst South African children and adolescents, although the overall prevalence differs amongst population groups and regions. The well known association between obesity and non-communicable diseases of lifestyle (including hypertension, coronary heart disease, type 2 diabetes and metabolic syndrome) highlights the burden that overweight and obesity place on the wellbeing of the nation.
The role of dairy in weight management
There is a negative association between dairy intake and weight gain
Many studies have investigated the association between aspects of dairy intake and body weight management. In recent years, these individual studies have been systematically reviewed and analysed to establish the strength of the evidence. Some conclusions from these comprehensive reviews are summarised below.
Dairy and dairy calcium limit weight gain
Findings suggest that people who consume milk or dairy are protected from weight gain and tend to be able to maintain a healthier weight. This suggests a negative association between dairy intake and weight gain: an increase in dairy intake is associated with a decrease in body mass index. Increasing calcium intakes from 400 mg per day to 1200 mg per day is associated with a decrease in body mass index from 25.6 kg/m² to 24.7 kg/m².
Consumption of calcium from dairy is linked not only to lower body weight but also to lower percentages of total body fat and fat in the abdominal area. It is well known that body composition and body fat distribution may be a more important risk factor for the development of non-communicable diseases than body weight.
Dairy calcium enhances weight loss and body fat decrease during energy restriction
Dairy has been found to have a beneficial effect in weight loss treatments. Dairy not only facilitates weight loss when it forms part of an energy restricted diet but also appears to maintain lean tissue in overweight people on weight loss diets. It has been suggested that there is a possible threshold effect, with more than 600–800 mg calcium needing to be consumed to promote fat loss. This effect seems to be specific to dairy calcium (as opposed to calcium supplements).
The mechanism to explain the link between dairy intake and weight management is not yet clear. But it is possible that dairy and/or the calcium from dairy:
- forms faecal, insoluble soap-like fatty acid complexes that reduce fat absorption
- regulates energy metabolism (e.g. through increased energy expenditure)
- affects fat metabolism a suggested by the ‘calcium hypothesis’ (e.g. lipolysis of adipocytes and fatty acid oxidation)
- increases satiety and stimulates food regulatory mechanisms (e.g. dairy protein such as whey may reduce spontaneous food intake).
Conclusion and recommendations
The health-promoting effects of dairy as part of a diet in line with the Food Based Dietary Guidelines are undisputed. Despite many unanswered questions with regard to the mechanism governing the link between dairy and weight management, research indicates that the mix of nutrients found in dairy products, especially calcium and protein, may play an important role in weight management. As dairy products naturally contain calcium, protein and other essential nutrients, consuming three servings daily may not only contribute to weight management but will also improve the overall nutritional quality of the diet.