7.4.5: Alcohol: The Anti-Nutrient
Alcohol is not a macronutrient your body requires. It provides 7 kcal per gram—almost as energy-dense as fat—but unlike fat, protein, or carbohydrate, alcohol cannot be stored by the body. Because ethanol is toxic, the body treats its elimination as an urgent priority, and this has cascading consequences for both body composition and health.
How alcohol sabotages fat loss:
- Fat oxidation halts. When you drink, your liver converts ethanol into acetaldehyde and then acetate. The body prioritises clearing this toxin, and while it does so, it effectively shuts down the oxidation (burning) of fat. Every hour you spend metabolising alcohol is an hour your body is not burning stored body fat.
- It displaces useful macros. The 7 kcal/g from alcohol provide zero protein, zero micronutrients, and zero structural benefit. A night of moderate drinking can easily add 500–1000 kcal of nutritionally empty energy.
- It increases appetite and lowers inhibition. Alcohol impairs decision-making and increases hunger signals. The post-drinking kebab or late-night pizza is not a coincidence—it is a pharmacological effect.
How alcohol impairs muscle growth:
Parr et al. (2014) demonstrated that consuming alcohol (1.5 g/kg of body mass) after resistance exercise suppressed muscle protein synthesis (MPS) by 24–37%, even when co-ingested with protein [7]. Alcohol attenuates the phosphorylation of mTORC1 signaling proteins—the same master growth switch we discussed in Chapter 1—directly blunting the muscle’s anabolic response to training.
Alcohol and cancer:
The International Agency for Research on Cancer (IARC), the cancer research arm of the World Health Organization, classifies ethanol in alcoholic beverages as a Group 1 carcinogen—the same category as tobacco smoke and asbestos [8]. There is a clear dose-response relationship: the more you drink, the higher your risk. Cancers of the oral cavity, pharynx, larynx, oesophagus, liver, colorectum, and female breast are all causally linked to alcohol consumption. There is no established safe threshold.
“Red wine is healthy because of resveratrol.” This claim does not withstand scrutiny. The concentration of resveratrol in a glass of wine is orders of magnitude below the doses used in cell-culture studies showing any benefit. To get a pharmacologically relevant dose, you would need to drink hundreds of glasses per day—at which point the ethanol would kill you long before the resveratrol helped. The net health effect of any amount of alcohol is negative.
The pragmatic position: There is no safe level of alcohol consumption. Occasional social drinking will not destroy your progress. But regular consumption—even moderate—actively sabotages both fat loss and muscle growth. If your goal is to optimise body composition and long-term health, less is better, and none is best.