Role of Dairy Products in Weight Maintenance
Condition: Obesity; Weight Gain
MeSH terms: Body Weight; Weight Gain
Study type: Interventional

Summary: 
      The goal of the current study is to determine the role of dairy in similarly preventing
      weight and fat re-gain in obese adults who have successfully completed a weight loss diet
      program.240 obese subjects will undergo a meal-replacement-based weight loss plan designed to
      produce a 10 kg weight loss in 8-12 weeks. Upon achieving the weight loss goal, subjects will
      be randomly assigned to either a low-dairy or high-dairy eucaloric weight maintenance diet
      for two years. Macronutrient distribution will be maintained constant and set at
      approximately the U.S. average. Primary outcomes include changes in body weight, body fat and
      anatomical distribution of fat (via dual x-ray absorptiometry) and resting metabolic rate and
      substrate oxidation (via respiratory calorimetry); Secondary outcomes include blood pressure,
      circulating glucose, insulin, lipids and calcitrophic hormones. on prevention of weight
      regain in humans has not yet been assessed in clinical trials.
    

Detailed description: 
      Dietary calcium plays a pivotal role in the regulation of energy metabolism, as we have found
      high calcium diets to attenuate adipocyte lipid accretion and weight gain during periods of
      over-consumption of an energy-dense diet and to increase lipolysis and preserve thermogenesis
      during caloric restriction, thereby markedly accelerating weight loss. Our studies of the
      agouti gene demonstrate a key role for intracellular Ca2+ in regulating adipocyte lipid
      metabolism and triglyceride storage, with increased intracellular Ca2+ resulting in
      stimulation of lipogenic gene expression and lipogenesis and suppression of lipolysis,
      resulting in adipocyte lipid filling and increased adiposity. Moreover, the increased
      calcitriol produced in response to low calcium diets stimulates adipocyte Ca2+ influx and,
      consequently, promotes adiposity, while higher calcium diets inhibit lipogenesis, promote
      lipolysis, lipid oxidation and thermogenesis and inhibit diet-induced obesity in mice.
      Notably, dairy sources of calcium exert markedly greater effects in attenuating weight and
      fat gain and accelerating fat loss. This augmented effect of dairy products versus
      supplemental calcium is likely due to additional bioactive compounds in dairy which act
      synergistically with calcium to attenuate adiposity. These concepts are confirmed by both
      epidemiological and clinical data which demonstrates that increasing dietary calcium results
      in significant reductions in adipose tissue mass in obese humans in the absence of caloric
      restriction and markedly accelerates the weight and body fat loss secondary to caloric
      restriction, while dairy products exert markedly greater (nearly two-fold compared to calcium
      supplements) effects. These data indicate an important role for dairy products in both the
      prevention and treatment of obesity. However, weight maintenance following successful weight
      loss (i.e. prevention of regain) is at least as important as strategies to initially achieve
      weight loss, as most individuals who successfully lose weight are not successful in
      maintaining this weight loss. We have recently demonstrated that ad libitum re-feeding of
      dairy-rich following weight loss in mice on an energy restricted mice prevented the
      suppression of adipose tissue lipolysis and fat oxidation that otherwise accompanies such
      re-feeding and markedly upregulated skeletal muscle fat oxidation. Consequently, although
      animals re-fed low calcium diets rapidly regained all of the weight and fat that had been
      lost, animals fed high calcium diets exhibited a shift in energy partitioning and a 50-85%
      reduction in weight and fat gain; moreover, dairy exerted markedly greater effects than
      supplemental calcium on weight and fat regain. However, the effect of dairy on prevention of
      weight regain in humans has not yet been assessed in clinical trials. Accordingly, the goal
      of the current study is to determine the role of dairy in similarly preventing weight and fat
      re-gain in obese adults who have successfully completed a weight loss diet program.

      340 obese subjects will undergo a meal-replacement-based weight loss plan designed to produce
      a 10 kg weight loss in 8-12 weeks. Upon achieving the weight loss goal, subjects will be
      randomly assigned to either a low-dairy or high-dairy eucaloric weight maintenance diet for
      two years. Macronutrient distribution will be maintained constant and set at approximately
      the U.S. average. Primary outcomes include changes in body weight, body fat and anatomical
      distribution of fat (via dual x-ray absorptiometry) and resting metabolic rate and substrate
      oxidation (via respiratory calorimetry); Secondary outcomes include blood pressure,
      circulating glucose, insulin, lipids and calcitrophic hormones.
    

Intervention name(s): Dairy Foods; Dairy Foods
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Adequate dairy (> 3 standard daily servings); < 1 standard dairy serving/day
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Obesity; Weight gain; regain; dairy; calcium