Drinking a gallon of milk a day provides about 2,400 calories and may help a person gain weight. It may also have some negative health effects, especially if practiced long term.

The gallon of milk a day (GOMAD) diet is exactly what it sounds like: a regimen that involves drinking a gallon of whole milk over the course of a day. This is in addition to your regular intake of food.

This “diet” isn’t a weight loss plan, but rather a “bulking strategy” for weightlifters looking to add muscle mass in a short amount of time. The idea is to drink a gallon of whole milk every day until your goal weight is reached. This usually takes two to eight weeks.

Overly enthusiastic GOMAD testimonials are plentiful on the internet. But is the diet necessary, safe, and worth possibly unpleasant side effects? Here’s a look at the pros and cons.

A gallon of whole milk provides roughly:

  • 2,400 calories
  • 127 grams (g) of fat
  • 187 g of carbohydrates
  • 123 g of protein

It’s not surprising that GOMAD works as far as helping individuals put on weight quickly. Liquid calories don’t make you feel as full as those from solid food, so it’s easier to drink an additional 2,400 calories than to eat them.

The absence of fiber in milk also makes it easier to gulp down an additional 2,400 calories than chew them. Fiber is especially filling, which is why it helps when you’re trying to lose weight.

To get 2,400 calories from solid food, you could eat:

  • 2 avocados (640 calories)
  • 3 cups of rice (616 calories)
  • 1 cup of mixed nuts (813 calories)
  • 1 1/2 cup diced chicken breast (346 calories)

It’s no wonder that gulping down 16 cups of milk seems like a more attractive and less time-consuming option.

Pros of GOMAD diet

  • Drinking a gallon of milk is less time-consuming than eating the equivalent 2,400 calories.
  • You’ll reach your goal weight quickly on this diet.
  • This diet may work well for weightlifters or bodybuilders.
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A gallon of milk provides very high amounts of certain nutrients. But that’s not always a good thing. Consider the 1,920 milligrams (mg) of sodium, 83 percent of the daily recommended limit according to the 2015-2020 Dietary Guidelines for Americans. That’s without eating or drinking anything else.

A gallon of milk also adds up to 80 g of saturated fat. That’s about 400 percent of the daily recommended limit, based on the guidelines. Some experts don’t agree that saturated fat is a nutrient that requires limits.

Calcium is one nutrient most Americans don’t get enough of. A gallon of milk a day delivers 4,800 mg, well surpassing the daily recommendation of 1,000 mg for most adults. Such a high daily intake of this mineral could be harmful.

Experts caution that men and women between 19 and 50 years old should not consume more than 2,500 mg of calcium a day. This is because of concerns about impaired kidney function and an increased risk of kidney stones.

Some studies show that people who consume high amounts of calcium might have increased risks of prostate cancer and heart disease, but more research is needed in this area. One 2014 study also suggested that too much milk might affect bone health.

You might argue that drinking a gallon of whole milk a day for a short period of time is unlikely to do much damage to your health. But GOMAD can result in uncomfortable gastrointestinal symptoms that can show up as early as day one.

Among them are bloating, nausea, and diarrhea. These symptoms are even felt by individuals who don’t report lactose intolerance or an allergy to milk protein.

Discomfort aside, this also demonstrates how GOMAD can interfere with daily life. Be prepared to carry milk with you throughout the day, as it’s difficult to drink 16 cups of milk in short periods of time.

Cons of the GOMAD diet

  • GOMAD can result in uncomfortable gastrointestinal symptoms such as bloating, nausea, and diarrhea.
  • You have to carry around milk with you throughout the day because it’s difficult to consume this much milk at two or three sittings.
  • A gallon of milk contains around 1,680 mg of sodium and 73 g of saturated fat, high above the daily recommended amounts.
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Adding a gallon of milk to your daily diet certainly addresses the caloric excess needed to gain weight and support muscle building (if one engages in muscle building physical activity, of course). But that doesn’t make GOMAD a good idea.

While some of the weight put on as a result of GOMAD will be muscle mass, a significant amount will also be fat. Your body can’t use that many calories all at once, so the leftovers will be stored as fat.

By comparison, a more carefully planned and less extreme diet over a longer period of time can help with a goal of gaining weight, with most of that coming from increased muscle mass.

GOMAD raises the same red flags that starvation diets do: chasing a short-term outcome using unsustainable methods that come with unpleasant side effects. It’s always a better idea to build healthful habits that can last for the long run.