Protein level and source in single meal influence voluntary intake during subsequent meal

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Coleman Murray (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Joseph L. Beverly

Abstract: Dietary protein has been shown to be more satiating than other macronutrients. The objective of this present study was to assess the acute effect of a meal differing in protein level and source on subsequent intake. Diets included 15%, 20%, 35%, and 50% levels with same and mixed protein sources over a series of five feeding trials. Protein sources included casein, egg white, and wheat gluten. Rats were adapted to a feeding schedule consisting of a 30 minute breakfast meal (20% of daily calories) provided 60 minutes into the dark period. On test days, ground chow was made available 60 minutes after the breakfast meal. The amount consumed during this test period was measured as an index of the satiating effect of the breakfast meal. A 5 hour ad libitum period concluded the dark period. During each study, each rat received all of the test diets without consuming the same diet on back to back days. There were no differences in the amount of diet consumed during the breakfast meal, nor were there differences in the total calories consumed during the entire 24 hour period on test days. When fed a normal protein level (15% or 20%) there was no effect of protein source on subsequent intake during the test period. When rats consumed a breakfast of 35% wheat gluten protein an increase in subsequent intake resulted; however, when 35% egg white protein was consumed there was a significant decrease in intake indicating that egg white was more satiating than wheat gluten. Mixed diets composed of a 15% or 20% casein protein base and an addition of 20% or 15%, respectively, egg white or wheat gluten protein, totaling 35% of calories as protein, were also assessed. Similar results were seen when rats consumed these mixed egg white/casein or wheat gluten/casein breakfast meal at a total of 35% of calories as protein. At the 50% protein level there was a decrease in subsequent intake, indicating the higher protein level was more satiating. Additionally, the different mineral profile of the 35% egg white diet was assessed showing that this was not a factor affecting the rat’s consumption as the diet of 35% of calories from casein protein with added minerals did not result in a decreased subsequent intake as was seen with the 35% egg white diet. These data support a difference between protein sources in their apparent satiating effect on a subsequent meal when fed to rats at 35% of calories. The three protein sources produced different effects on subsequent intake with egg white decreasing intake, wheat gluten increasing intake, and casein having no effect. All of these effects are a result of an acute response to a randomly assigned breakfast meal at a limited amount of calories. The duration of the effect was short, as total caloric intake on test days was not affected by diet fed at the breakfast meal.

Additional Information

Language: English
Date: 2017
Egg White, Protein, Satiety, Wheat Gluten
Food $x Protein content
Proteins in animal nutrition
Rats $x Feeding and feeds

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