Alcohol (ethanol) provides 7 calories per gram — making it nearly as calorie-dense as fat but with zero nutritional value. Its effects on nutrition and health are significant.

How alcohol is metabolized:

1. Absorbed rapidly in stomach and small intestine
2. Metabolized primarily in liver (alcohol dehydrogenase → acetaldehyde → acetate)
3. Liver prioritizes alcohol metabolism — delays fat burning

Nutritional effects of excess alcohol:

• Impairs absorption of B vitamins (especially thiamine/B1, B12, folate)
• Depletes magnesium, zinc, potassium
• Damages gut lining, increasing intestinal permeability
• Causes fatty liver (alcoholic steatosis) with chronic heavy use
• Disrupts sleep architecture — reduces REM sleep

Cancer risk: Alcohol is classified as a Group 1 carcinogen. Even moderate drinking increases risk of breast, colon, liver, and esophageal cancer.

Reference:

Wikipedia: Alcohol and health

https://en.wikipedia.org/wiki/Alcohol_(drug)