Previous research found that moderate alcohol consumption can lead to an increase in food energy intake. But what about the intake of specific macronutrients such as carbs, fat and protein? A recent systematic review1, published in Obesity Reviews, found that there seems to be a dose-dependent effect on macronutrient intake. The decrease in carbohydrate intake with heavier alcohol consumption was most consistent.
What is already known? A previous meta-analysis looked at experimental studies and found that moderate alcohol consumption increases food energy intake. For heavy drinking, this effect was not significant.2 However, total energy intake did increase, meaning that the participants did not reduce their food intake to compensate for the energy they consumed through the alcoholic beverage.
What does this study add? This is the first systematic review that looks at the dose-dependent effect of alcohol consumption on specific macronutrient intake.
The American scientists from University of Michigan and California included 30 studies in this systematic review: about half experimental and half observational. In total, there are almost 274.000 participant.
Single occasion of drinking in laboratory
In the experimental studies, participants could drink for 5 to 30 minutes. Ten minutes to five hours later, ad libitum food intake was measured. Many of the studies found that moderate alcohol consumption was associated with an increase in food intake. This effect was less pronounced with heavy alcohol consumption, which is consistent with the results of the previous meta-analysis2.
When a study found an effect on the specific macronutrient intake, the single occasion of drinking most often increased the intake of fat and protein, and, to a lesser extent, increased intake of refined and unrefined carbohydrates.
Real-life drinking habits
When we look at the food intake associated with real-life drinking habits, a different pattern appears. Similar to the single occasion of drinking in a laboratory setting, light and moderate drinking were often associated with greater intake of fat and protein and, to a lesser extent, with greater intake of unrefined and refined carbohydrates (though two studies found a decrease in unrefined carbohydrates). However, frequent heavy drinking was linked with intake of fewer refined and unrefined carbohydrates and, to a lesser extent, with lower protein and fat intake. It should be stressed that this does not mean that heavy alcohol consumption decreases total energy-intake, as alcohol itself also contains a lot of calories.
As the previous meta-analysis also found, there seems to be a dose-dependent relation between alcohol consumption and food intake. This review gives a couple of possible explanations. The first is that alcohol consumption stimulates dopamine release. In low quantities this may increase motivation for rewarding substances including food3. But in high quantities, the neural pathways are saturated with dopamine, which may decrease the craving for foods. Additionally, in low quantities, alcohol causes stimulatory effects such as a positive mood4,5. But with high alcohol consumption, alcohol causes sedative effects, which may decrease the motivation to eat. Another explanation is that alcohol can causes gastric expansion and gives you a sensation of fullness when consumed in high quantities.
The fact that the consumption of carbohydrates especially decreases, could be because alcohol itself is a fermented carbohydrate, which may decrease the motivation the craving for carbohydrates6. A process that could be mediated by the gut-brain processing.
- Systematic approach
- No meta-analysis could be performed
- No differentiation between types of macronutrients (e.g. type of fat)
- No inclusion of overall diet quality
1 Cummings, J. R., Gearhardt, A. N., Ray, L. A., Choi, A. K., & Tomiyama, A. J. (2019). Experimental and observational studies on alcohol use and dietary intake: a systematic review. Obesity Reviews.
2 Kwok, Alastair, Aimee L. Dordevic, Gemma Paton, Matthew J. Page, and Helen Truby. “Effect of alcohol consumption on food energy intake: a systematic review and meta-analysis.” British Journal of Nutrition (2019): 1-15.
3 Weiss, F., Lorang, M. T., Bloom, F. E., & Koob, G. F. (1993). Oral alcohol self-administration stimulates dopamine release in the rat nucleus accumbens: genetic and motivational determinants. Journal of Pharmacology and Experimental Therapeutics, 267(1), 250-258.
4 Martin, C. S., Earleywine, M., Musty, R. E., Perrine, M. W., & Swift, R. M. (1993). Development and validation of the biphasic alcohol effects scale. Alcoholism: Clinical and Experimental Research, 17(1), 140-146.
5 Pohorecky, L. A. (1977). Biphasic action of ethanol. Biobehavioral Reviews, 1(4), 231-240.
6 Wurtman, J. J., Moses, P. L., & Wurtman, R. J. (1983). Prior carbohydrate consumption affects the amount of carbohydrate that rats choose to eat. The Journal of nutrition, 113(1), 70-78.