Adverse Metabolic Effects of Dietary Sugar
Condition: Chronic Disease of Cardiovascular System; Type 2 Diabetes; Obesity
MeSH terms: Chronic Disease
Study type: Interventional

Summary: 
      It is not known whether consumption of excessive amounts of sugar can increase risk factors
      for cardiovascular disease or diabetes in the absence of increased food (caloric) intake and
      weight gain, nor whether the negative effects of sugar consumption are made worse when
      accompanied by weight gain. This study will investigate the effects of excess sugar when
      consumed with an energy-balanced diet that prevents weight gain, and the effects of excess
      sugar when consumed with a diet that can cause weight gain. The results will determine
      whether excess sugar consumption and excess caloric intake that lead to weight gain have
      independent and additive effects on risk factors for cardiovascular disease or diabetes, and
      will have the potential to influence dietary guidelines and public health policy.
    

Detailed description: 
      Recent studies have demonstrated that consuming high fructose corn syrup (HFCS)- or
      sucrose-sweetened beverages increased lipid/lipoprotein risk factors for cardiovascular
      disease (CVD) in healthy adults compared with iso-caloric amounts of glucose or low-fat milk.
      The longest of these studies, which utilized a 6-month intervention, also showed increased
      liver and muscle TG and increased visceral adipose deposition. Neither of these studies found
      differences in weight gain between subjects consuming HFCS/sucrose beverages compared with
      control beverages. These results suggest that it is not just excess calories and weight gain
      that mediate the effects of dietary sugar/fructose on the development of metabolic disease;
      rather, dietary sugar per se is also a contributor. However, it is not known whether
      consumption of excessive amounts of sugar can increase risk factors for metabolic disease in
      the absence of positive energy balance and weight gain, nor whether the adverse effects of
      sugar consumption are exacerbated by weight gain. This study will compare the contribution of
      sugar with the contribution of energy level to the increases in risk factors for metabolic
      disease induced by consumption of HFCS-sweetened beverages under energy-balanced or ad
      libitum conditions. The investigators will measure risk factors and processes associated with
      metabolic disease in 4 groups of young, healthy adults who will consume 1) 0%, 2) or 25% of
      energy requirement as HFCS-sweetened beverages for 8 weeks with an energy-balanced diet for 6
      weeks; 3) 0%, or 4) 25% of energy requirement as HFCS-sweetened beverages for 8 weeks with an
      ad libitum diet for 6 weeks. All diets, formulated to achieve a comparable macronutrient
      intake (55% energy as carbohydrate, 35% fat, 15% protein) among all 4 experimental groups,
      will be provided to the subjects throughout the entire study. The investigators hypothesize
      that under energy balanced (EB) condition that prevent body weight gain, consumption of
      HFCS-sweetened beverages will result in adverse metabolic effects compared with
      aspartame-sweetened beverages. Consumption of HFCS-sweetened beverages with the ad libitum
      (AL) diet will result in increased energy intake and body weight gain compared with
      aspartame-sweetened beverages, and will also result in adverse metabolic effects that are
      more marked than with consumption of HFCS-sweetened beverages with the energy-balanced diet.
      These results will demonstrate that consumption of HFCS-sweetened beverages increases risk
      for metabolic disease both directly, via the adverse effects of fructose on lipid and
      carbohydrate metabolism, and indirectly, via the effects of HFCS-sweetened beverages to
      promote excess energy intake and body weight gain. These findings will have the potential to
      influence dietary guidelines and public health policy.
    

Intervention name(s): high fructose corn syrup; aspartame; Energy-balanced diet; Ad libitum diet
Intervention type(s): Other; Other; Other; Other
Intervention description(s): High fructose corn syrup provided as 15% HFCS/85% water (weight/weight) fruit-flavored beverage; Aspartame provided as 0.04% aspartame/99.96% water (weight/weight), fruit-flavored beverage; Provided in quantities that equal energy requirement. Formulated such that the overall macronutrient intake; including beverage; equal 45%/5% energy requirement at complex/simple carbohydrate, 35% energy requirement as fat, 15% energy requirement as protein.; Provided in quantities that exceed energy requirement by approximately 25%. Formulated such that the overall macronutrient intake; including beverage; equals approximately 45%/5% energy requirement at complex/simple carbohydrate, 35% energy requirement as fat, 15% energy requirement as protein.
Other intervention name(s): sugar, HFCS, high fructose corn syrup-55, HFCS-55; non-caloric sweetener; Weight-maintaining diet; Positive-energy diet
Allocation: Randomized
Intervention model: Factorial Assignment
Masking: Double (Participant, Care Provider)
Primary purpose: Basic Science
Keywords: High fructose corn syrup; Sugar