The effect of non-nutritive sweeteners on body weight in rats.

Artificial sweeteners are used to provide a sweet taste to a food while removing the calories associated with sugar. The importance of non-nutritive sweeteners (NNS) for the control of body weight has never been proved. In this long-term study, 81 rats fed ad libitum on chow and water were given either an 11% sucrose solution, a solution artificially sweetened with saccharin and aspartame or served as controls. Over an 8-week period, the sucrose rats gained considerable weight while the NNS rats showed the same weight gain as controls. When the sweetened solutions were switched, obese sucrose rats lost weight during the next 8 weeks while rats previously on NNS gained weight rapidly. The results show that substitution of artificial sweeteners for sugars prevents weight gain and promotes weight loss in rats.

Diet-induced changes in serum transaminase and triglyceride levels in healthy adult men. Role of sucrose and excess calories.

Serum transaminase levels were measured as part of a study on the physiologic control of food intake. Twenty-one men, 15 nonobese and six obese, were housed on a metabolic ward for 30 days where they received ad libitum a baseline diet of conventional foods containing 25 to 30 percent of total calories as sucrose for 18 days and a calorically diluted diet containing less than 10 percent sucrose for 12 days. Serum glutamic pyruvic transaminase (SGPT) and serum glutamic oxaloacetic transaminase (SGOT) levels rose significantly when subjects consumed the baseline diet and returned to their original levels on the calorically diluted aspartame-sweetened diet. Markedly abnormal transaminase levels developed in two subjects on the baseline diet and they had to be discharged from the study. Correlations between various components of the diet and enzyme changes suggested that both surplus calories and a high sucrose intake played a role in the elevation of enzyme levels. Serum triglyceride levels also showed a significant reduction when the subjects were switched from the baseline to the calorically diluted diet. In a second study designed to test systematically the role of sucrose on SGPT and SGOT levels and on serum triglyceride levels, six nonobese subjects received a carefully controlled liquid diet, relatively high in linoleic acid content, containing 50 percent of total calories as either sucrose or maltose. In comparison with the first study, sucrose had a smaller but still significant effect on the levels of both enzymes, but there was no significant effect on triglyceride levels.

Caloric regulation in normal-weight men maintained on a palatable diet of conventional foods.

The spontaneous food intake of six normal-weight male volunteers was measured for 24 days while the subjects were inpatients on a metabolic unit. They were fed a palatable diet of conventional foods and were kept unaware that their food intake was being measured. On days 7-18 the caloric content of their diet was covertly reduced by 25% by substituting aspartame-sweetened analogues for all menu items containing sucrose. Subjects did not alter their food intake for 3 days. Then between days 4-6 on the aspartame diet, they increased their intake to compensate for 40% of the missing calories. Food intake stabilized at 85% of baseline and remained the same for the rest of the 12-day dilution period. Subjects did not show a shift in either sweetened or unsweetened food choices while their diet was being diluted. In adjusting for the missing calories, they simply ate more of their customary diet. The replacement of sucrose by aspartame tended to curb the weight gain observed on the baseline diet.

An experimental model for assessing effects of anorectics on spontaneous food intake of obese subjects.

Ad libitum access to food by use of a platter service is a new method for studying spontaneous food intake in obese human subjects. The effect of diethylpropion on energy intake was evaluated by the platter-service method in 2 overweight adult male subjects hospitalized on a metabolic unit for 41 days. This double-blind experiment was divided into 12 consecutive 3-day study periods during each of which the subjects received either 25 mg diethylpropion or a matching placebo before each meal. In this design protocol the 12 study periods provided 6 consecutive drug-placebo trials for each subject. To encourage ad libitum ingestion, food was served "family style" from large platters and pitchers at meals, and snacks were always available. Subjects were not aware that their intake was being monitored. On diethylpropion administration both subjects had an average decrease in energy intake of 11% and 15% (p less than 0.005). The platter service model, which provides a near-natural eating situation under systematic control, appears to be a useful and sensitive method for assessing effects of anorectic drugs on spontaneous food intake.

Effect of covert nutritive dilution on the spontaneous food intake of obese individuals: a pilot study.

The present study investigated the feasibility of a new experimental approach for studying the effect of covert nutritive dilution on the spontaneous food intake of obese individuals. Eight obese subjects were studied as inpatients on a metabolic unit for 15 days during which time they were unaware that their food intake was being monitored. A platter method of food presentation encouraged ad libitum ingestion. Caloric dilution was achieved by replacing sucrose-containing products with aspartame-sweetened analogues in an otherwise normal diet. During the base-line period the subjects spontaneously ate sufficient conventional food to maintain or even slightly increase body weight. Covert substitution of aspartame-sweetened products for their sucrose counterparts resulted in an immediate reduction in spontaneous energy intake of approximately 25%. The aspartame analogues were as well accepted as their conventional counterparts, as indicated by the equal quantity of each consumed. These preliminary results demonstrate that, in a metabolic ward setting, it is possible to maintain the spontaneous food intake of obese individuals at levels sufficient to preserve body weight and arbitrarily to decrease those levels of intake by 25% or more through covert changes in the caloric density of the diet.