Dietary Components and Satiety

December 30, 2002

Here is some recent research which relates to the discussions that we have

been sharing on dieting:

Am J Clin Nutr 2003 Jan;77(1):91-100

Meals with similar energy densities but rich in protein, fat, carbohydrate,

or alcohol have different effects on energy expenditure and substrate

metabolism but not on appetite and energy intake.

Raben A, Agerholm-Larsen L, Flint A, Holst JJ, Astrup A.

BACKGROUND: It has been suggested that the satiating power of the 4

macronutrients follows the oxidation hierarchy: alcohol >protein >

carbohydrate > fat. However, the experimental evidence for this is still

scarce.

OBJECTIVE: The goal was to investigate the effects on appetite, energy

intake and expenditure, and substrate metabolism of meals rich in 1 of the 4

macronutrients.

DESIGN: Subjective appetite sensations, ad libitum food intake, energy

expenditure, substrate metabolism, and hormone concentrations were measured

for 5 h after breakfast meals with similar energy density and fiber contents

but rich in either protein (32% of energy), carbohydrate (65% of energy), fat

(65% of energy), or alcohol (23% of energy). Subjects were normal-weight,

healthy women (n = 9) and men (n = 10) studied in a crossover design.

RESULTS: There were no significant differences in hunger or satiety

sensations or in ad libitum energy intake after the 4 meals. Diet-induced

thermogenesis was larger after the alcohol meal (by 27%), whereas protein

produced an intermediary response (17%; NS) compared with carbohydrate and

fat (meal effect: P<0.01). After the alcohol meal, fat oxidation and leptin

concentrations were greatly suppressed (meal effects, P<0.0001 and P<0.05)

and triacylglycerol concentrations were as high as after the fat meal.

CONCLUSION: Intake of an alcohol-rich meal stimulates energy expenditure but

suppresses fat oxidation and leptin more than do isoenergetically dense

meals rich in protein, carbohydrate, or fat. Despite differences in substrate

metabolism and hormone concentrations, satiety and ad libitum energy intake

were not significantly different between meals. Our data, therefore, do not

support the proposed relation between the macronutrient oxidation hierarchy

and the satiety hierarchy.

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Dr Mel C Siff

Denver, USA

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