Energy Intake, Weight Gain and Fat Deposition in Rats Fed Flavored, Nutritionally Controlled Diets in a Multichoice (“Cafeteria”) Design

Abstract

The effect of flavor variety on diet selection, energy intake, weight gain and fat deposition was studied in male rats fed flavored, nutritionally controlled, purified diets in a multichoice "cafeteria" (CAF) arrangement. Serum insulin, L-3,3',5-triiodothyronine (T3) and thyroxine (T4) levels were also determined. Rats fed nutritionally balanced diets containing a variety of preferred flavors and textural forms ad libitum in a CAF design did not consume more energy nor did they gain more weight than rats fed a single choice of nutritionally balanced diet with no modifications in flavor or texture. Feeding high fat, high sucrose diets containing a variety of flavors in a CAF arrangement resulted in higher energy intake, body weight gain, lipid content in fat pads and serum T3 levels than did feeding the nutritionally balanced diet. However, the high fat diet with no added flavors also resulted in an energy intake, body weight gain and lipid content of fat pads at a level equal or close to that produced by the CAF feeding of the flavored, high fat, high sucrose diet. It is therefore concluded that the effect of a variety of food flavors on hyperphagia and fat deposition is of minor importance in purified diets compared to the stimulating effect of the fat in the diet.

Effect of altering the variety of sensorially distinct foods, of the same macronutrient content, on food intake and body weight in men

“…It appears form this study that the rats failed to decrease food intake in response to the higher energy density of the higher fat foods (Naim et al, 1985). This effect has now been repeatedly found in rodents (Warwick & Schiffman, 1992) and humans (Blundell & Stubbs, 1997).…”

“…Rats fed a high-fat diet with no added¯avours and textures consumed more energy and gained more weight, as did rats fed to a high-fat, highsucrose diet to which¯avours and textures had been added (cafeteria arrangement). These latter two diets promoted hyperphagia and weight gain over the 23 days of the study while simply altering sensory variety did not (Naim et al, 1985).…”

“…It is important to determine whether the nutritional or sensory attributes of a varied palatable diet promote greater energy intakes or whether both factors may play a role in elevating energy intake. In this regard the work of Naim et al has been important in dissociating the sensory versus nutritional determinants of hyperphagia in one rodent model Ð the rat (Naim et al, 1985;Naim & Kare, 1991). In their experiments Naim et al altered sensory variety by modi®cations of the¯avour and texture of nutritionally balanced (and nutritionally identical) diets (Naim et al, 1985).…”

“…In this regard the work of Naim et al has been important in dissociating the sensory versus nutritional determinants of hyperphagia in one rodent model Ð the rat (Naim et al, 1985;Naim & Kare, 1991). In their experiments Naim et al altered sensory variety by modi®cations of the¯avour and texture of nutritionally balanced (and nutritionally identical) diets (Naim et al, 1985). They also altered the nutrient content by partially replacing cornstarch with fats and sugars.…”

“…This effect has now been repeatedly found in rodents (Warwick & Schiffman, 1992) and humans (Blundell & Stubbs, 1997). While shorter-term studies in rodents have shown that increases in the variety of sensorially distinct but nutritionally similar foods can elevate food and energy intake (Treit et al, 1983), the 23-day study by Naim suggested that these effects do not persist in the longer term (Naim et al, 1985). In humans, increased variety of sensorially distinct foods promotes energy intake in the short term, but it is not known if this effect persists beyond the manipulated meal.…”