The current obesity epidemic appears to be linked to increasing availability of highly palatable, energy-dense, Western Style foods, with the relative contributions of Sugar-Sweetened Beverages (SSBs) remaining somewhat contentious. Animal studies permit investigation of the response to a variety of cafeteria foods in the absence and presence of 10% liquid sucrose, under controlled conditions.
Here, we sought to determine effects on body weight and macronutrient preference over time, in female rats as most studies to date have focused on males. Moreover, as adolescent intake of discretionary foods is high, we commenced diet in the pre-pubertal window.
5 week-old female Sprague Dawley rats were provided ad libitum access to one of four diets: standard chow (chow), standard chow + 10% sucrose (chow+sucrose), cafeteria diet (caf), and cafeteria diet + 10% sucrose (caf+sucrose). All groups had access to potable water and chow. Rats on cafeteria diet received a selection of common cafeteria foods, including biscuits, cake, dim sims, pie and chips, which were changed daily to provide choice.
Both cafeteria groups consumed more energy relative to chow-fed groups. Daily energy intake ranged from 244kJ in chow rats to 806kJ in caf+sucrose rats (p<0.01) compared to 610kJ in caf. Over 12 weeks, caf+sucrose rats more than doubled their starting weight, compared to 30%, 49%, 81% increases in chow, chow+sucrose and caf groups, respectively. We observed significant shifts in relative intake of protein, fat and carbohydrate over time. 10% sucrose availability led to gradual reductions in proportional intake of fat and protein. Chow+sucrose rats consumed 52% of their energy as sucrose versus 12% in caf+sucrose rats (p<0.01).
Thus, female rats on a high choice cafeteria diet overconsumed palatable food, and the addition of liquid sucrose drove intake further. Currently, we are examining the effects of macronutrient profile on other metabolic outcomes.