Where GOMAD came from
The idea became popular in strength-training circles in the 2000s, usually paired with a simple beginner barbell programme. The logic is blunt: young, skinny lifters often can’t eat enough solid food to grow, but they can drink. Milk is cheap, filling only briefly, and carries protein, fat and sugar together.
What most people don’t realise is that drinking milk in very large quantities is not new at all. A century ago, doctors and health writers such as Bernarr Macfadden were prescribing four to six quarts a day as a “milk diet”. You can read his complete 1923 book, The Miracle of Milk, free on this site.
The numbers in a gallon of milk
Figures vary slightly by brand and fat level, but for a US gallon (16 cups) of whole milk you are looking at roughly:
- Calories: about 2,400
- Protein: about 120–125 g
- Fat: about 125–130 g, of which around 70 g is saturated
- Sugar (lactose): about 190 g
- Calcium: about 4,500 mg
A note for readers in Britain: an imperial gallon is larger (4.5 litres), so a “UK GOMAD” is closer to 2,900 calories. Most people who try it in the UK use four litres, which lands close to the American version.
Does GOMAD work?
For its narrow purpose, yes. If you are underweight, training hard and genuinely failing to eat enough, an extra 2,000-plus calories a day will move the scales. People commonly report gaining several kilograms in the first month.
The catch is what that weight is made of. Muscle can only be built so fast. Once you are eating well above what your training can use, the extra mostly becomes body fat. Some of the early jump is also water and gut contents, not tissue.
The common side effects
- Bloating and loose stools, especially in the first fortnight
- Lactose trouble for anyone who is even mildly intolerant
- Acne flare-ups, which some people link to high dairy intake
- Feeling full all day, which pushes out vegetables, fruit and fibre
- Very high saturated fat and calcium intake, well above usual guidelines
Who should not try it
Skip GOMAD if you have kidney disease, heart disease, high cholesterol, diabetes, a history of kidney stones, a milk allergy or lactose intolerance. It is also not a sensible plan for children, during pregnancy, or for anyone who is not actually underweight. If you are unsure, speak to your GP or a registered dietitian first.
A gentler version: “half-GOMAD”
Most coaches now suggest a softer approach that keeps the benefit without the downside:
- Drink 1–2 litres a day, not 4. That still adds 650–1,300 calories.
- Spread it out. A large glass with each meal and one after training.
- Keep eating real meals. Milk should add to your diet, not replace it.
- Choose semi-skimmed if fat gain is creeping up faster than strength.
- Track your waist as well as your weight. If the waist climbs quickly, cut back.
GOMAD versus the old milk diet
They look similar but had different aims. GOMAD is a bulking tool used alongside full meals and heavy training. The historic milk diet was milk only, often with rest in bed, and was promoted as a treatment for illness. We explain that older plan in plain English in The Milk Diet Explained.
Frequently asked questions
How much weight can you gain on GOMAD? Many people gain 3–5 kg in the first month, but much of it is fat and water rather than muscle.
Is GOMAD safe? For a healthy, underweight adult for a few weeks it is usually tolerated, though uncomfortable. It is not suitable for people with kidney or heart problems, diabetes or lactose intolerance.
Can I do GOMAD with skimmed milk? You can, but you lose about half the calories, which defeats the point for most people. Semi-skimmed is a reasonable middle ground.
This article is general information, not medical advice. Please speak to your doctor or a registered dietitian before making big changes to your diet.