Dietary protein suppresses appetite more than do carbohydrates and fat
Updated: Mar 28, 2019
Have you ever wondered if your choice of foods affects how much you eat and how quickly you get full?
For instance, does it make a difference if you begin your day with a piece of carbohydrate-rich toast or a slice of cheese in terms of how much you end up eating at breakfast and lunch?
These questions are, indeed, important in this era of burgeoning obesity and all of its associated health problems.
Currently, urban legend suggest that high- protein foods are the most satiating, and high-carbohydrate choices the least.
But not all research supports this contention, possibly due to differences in experimental design or subjects’ characteristics. For instance, men might respond differently than women.
In addition, many studies have not systematically controlled for important dietary variables, like calories, that might make results difficult to interpret and compare.
To help fill this research gap, researchers conducted a carefully-controlled dietary intervention study with 23 men and 17 women. Their study is published in The Journal of Nutrition and summarized here.
To be eligible for the study, individuals needed to be between 20 and 50 years old, healthy, nonvegetarian, not on a diet, and have a positive relationship with food (as assessed by a commonly-used questionnaire).
Each subject then agreed to report to the metabolic laboratory on several mornings, each time after consuming a standard meal the night before.
During each of these visits, participants consumed an experimental beverage containing a specific amount of protein, carbohydrate, and fat; all treatments provided the same level of calories and were consumed in equal volumes.
Several hours later, subjects were offered a lunch meal of tortellini with tomato sauce and cheese and asked to consume as much as they liked.
The researchers then investigated how each “preload” beverage influenced feelings of fullness, subsequent lunch consumption, and blood levels of several hormones and metabolites.
Data clearly show that, regardless of the preload beverage’s fat and carbohydrate contents, consuming a high-protein version suppressed appetite the most.
Consuming the high-protein treatment also lowered blood glucose and raised glucagon-like peptide 1 concentrations. This is especially interesting because glucagon-like peptide 1 is known to suppress appetite.
These effects were generally opposite for the high-fat preload (suggesting that consuming fatty foods impact appetite less than protein and carbohydrate) and the same in men and women.
Although there were no differences in the amount of food consumed at lunch, the researchers concluded “adjusting the nutritional profile of a meal, especially replacing fat with protein, could make dieting more endurable.”
Citation: Dougkas A, Őstman E. (2016). Protein-enriched liquid preloads varying in macronutrient content modulate appetite and appetite-regulating hormones in healthy adults. Journal of Nutrition 146: 63745.
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