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What happens if you drink 3 glasses of milk a day?

Drinking milk is associated with many health benefits, but consuming too much may cause problems. This article reviews the effects of drinking 3 glasses of milk per day.

Milk Nutrition

Milk is rich in important nutrients like calcium, protein, vitamins A and D, phosphorus, and riboflavin (1). One 8-ounce (240-ml) glass provides:

  • Calories: 146
  • Protein: 8 grams
  • Calcium: 276 mg (28% of the Daily Value)
  • Vitamin D: 24% of the Daily Value
  • Riboflavin: 26% of the Daily Value
  • Phosphorus: 22% of the Daily Value
  • Vitamin A: 10% of the Daily Value

Given this nutritional profile, drinking 3 glasses of milk per day would provide:

  • Calories: 438
  • Protein: 24 grams
  • Calcium: 828 mg
  • Vitamin D: 72% of the Daily Value
  • Riboflavin: 78% of the Daily Value
  • Phosphorus: 66% of the Daily Value
  • Vitamin A: 30% of the Daily Value

Benefits of Drinking Milk

Here are some of the top health benefits associated with drinking milk:

Strong Bones

Milk is one of the best sources of calcium, providing 276 mg per 8-ounce (240-ml) glass. Calcium is essential for building and maintaining strong bones (2).

Studies show that consuming adequate amounts of calcium and vitamin D — both found in milk — may reduce the risk of osteoporosis and bone fractures later in life (3, 4).

Muscle Mass

Milk provides a combination of protein and amino acids that’s beneficial for building muscle. Some research shows it can promote muscle growth when paired with resistance exercise (5).

One 12-week study in 61 men found that those who drank milk after working out had greater muscle and strength gains than those who drank soy or carb-based shakes (6).

Heart Health

Drinking milk may benefit heart health in a variety of ways.

Some studies indicate that dairy intake reduces levels of total and LDL (bad) cholesterol, lowering heart disease risk (7, 8).

Other research links dairy intake to decreased blood pressure. This is attributed to specific proteins like casein and whey (9).

One review of 29 studies found consuming dairy products like milk to reduce systolic blood pressure by 2.11 mmHg and diastolic blood pressure by 1.13 mmHg, on average (10).

Weight Control

Interestingly, some research suggests that drinking milk could aid weight control.

One study in 145 women found that increased dairy intake led to less fat gain over time, even when the same number of calories was consumed (11).

Another study had similar findings, reporting that eating dairy products was linked to reduced body fat and belly fat in middle-aged adults (12).

The protein and nutrients in milk may promote feelings of fullness, which could keep hunger at bay and prevent overeating (13).

Other Benefits

Drinking milk has also been linked to other potential benefits, including:

  • Reduced risk of diabetes. Drinking milk may improve insulin secretion and blood sugar control (14).
  • Lower colorectal cancer risk. One review linked dairy intake to a 15% lower risk of colorectal cancer (15).
  • Improved dental health. Milk provides calcium and phosphorus, which help strengthen tooth enamel (16).
  • Hydration. Milk is over 85% water, making it very hydrating (1).

Downsides of Drinking Too Much Milk

Despite the many benefits of milk, drinking more than about 2–3 glasses (16–24 ounces or 500–750 ml) per day may cause some adverse effects, such as:

Weight Gain

Although some studies show that milk could aid weight loss, others indicate that it may have the opposite effect.

One study found that intake of high-fat dairy was associated with increased belly fat in adults (17).

Another study reported that giving schoolchildren milk instead of sugar-sweetened beverages increased body mass index (BMI) by 0.7 kg/m2 (18).

High Cholesterol

Some research indicates that high intakes of saturated fat and cholesterol from milk could contribute to high cholesterol levels in some people (19).

One study in 22 men found that drinking whole milk 3 times per day for 3 weeks significantly increased LDL (bad) cholesterol, compared to drinking skim milk (20).

Prostate Cancer

Numerous studies link high dairy intake to an increased risk of prostate cancer. However, the link between milk consumption and prostate cancer remains controversial (21, 22).

One study found that drinking more than 1 glass (240 ml) of milk per day increased prostate cancer risk by 30% compared to drinking less than 1 glass per week (23).


Some research associates milk consumption with acne development in adolescents. Hormones found in milk may contribute to acne (24).

Still, evidence on dietary factors and acne is conflicting. Further high quality studies are needed (25).

Milk Allergy

About 0.5–3.5% of children have an allergy to cow’s milk (26).

For people with a milk allergy, drinking milk can cause symptoms like hives, wheezing, vomiting, and diarrhea (27).

Lactose Intolerance

Lactose intolerance affects around 65% of the global population. It’s triggered by lactase deficiency, making it difficult to digest lactose, the main carb in milk (28).

Common symptoms include bloating, gas, abdominal pain, diarrhea, and nausea after consuming dairy products (29).

Recommended Daily Intake

How much milk you should drink daily depends on your age, gender, and specific health goals.

The Dietary Guidelines for Americans recommend the following daily dairy intakes:

Age Recommended Amount
1–3 years 2 cups (16 oz or 500 ml)
4–8 years 2.5 cups (20 oz or 600 ml)
9–18 years 3 cups (24 oz or 750 ml)
19–50 years 3 cups (24 oz or 750 ml)
51+ years 3 cups (24 oz or 750 ml)

Pregnant and breastfeeding women require 3 cups (24 ounces or 750 ml) per day to support infant development (30).

However, not everyone needs 3 glasses of milk per day. Dietary needs vary based on your gender, age, activity levels, health status, and personal preferences.

The Bottom Line

Milk is rich in important nutrients like calcium, vitamin D, and protein. Drinking milk has been linked to bone health, muscle growth, weight control, and lower blood pressure.

However, too much dairy may contribute to weight gain, prostate issues, and acne in some individuals. Around 65% of people are lactose intolerant and experience digestive distress with dairy.

Moderate your milk intake based on your own dietary needs and tolerance. Most health authorities recommend 2–3 glasses (16–24 ounces or 500–750 ml) of milk per day as part of a healthy diet.