Is Milk Bad For You? What 30 Studies Have to Say

For years, milk has been touted as one of the healthiest foods you can eat.

It’s packed full of protein, calcium, and other nutrients, and it’s delicious to boot.

It’s also hugely popular among bodybuilders and people just generally interested in improving their body composition.

If you go asking around the gym for the best way to gain muscle and strength as quickly as possible, it won’t take long until you’re told to just lift heavy weights and drink a gallon of milk per day.

(The heavy weightlifting is a great idea, but the “GOMAD”? Not so much…)

Recently, though, milk has come under heavy fire from the health “gurus” of the world who not only question its nutritional value, but go as far as labeling it a poison responsible for all kinds of disease and dysfunction.

Drink milk, they say, and thanks to the lactose, pus, blood, hormones, and other “unhealthy” substances it contains, you’ll be more likely to gain weight, weaken your bones, and even get cancer and die.

Many of the people making these arguments seem to have logic and science on their sides, too.

Maybe they’re right? Maybe milk isn’t all it’s cracked up to be? Maybe we’d all be better off without it?

Well, as you’ll soon see, although the case against milk can be made to sound convincing, it’s based on trumped up charges.

When you analyze the bulk of the research, which we’re going to do in this article, the takeaway is clear:

Milk is not a magic bullet for bone health, muscle gain, or general wellbeing, but it doesn’t deserve condemnation, either, and you probably don’t need to stop drinking it.

Let’s find out why, starting with square one:

What is milk, exactly?

What Is Milk, Exactly?

A simple question, I know, but most people can’t quite answer it.

Milk is a combination of water, whey and casein protein, globules of fat, lactose (a simple sugar), and some vitamins and minerals.

In terms of calories and “macros,” a cup of whole cow’s milk contains about 145 calories, 8 grams of protein and fat and 13 grams of carbohydrate.

Low-fat varieties of milk contain more or less the same amount of carbs and protein, but less fat and thus fewer calories. For instance, a cup of skim milk has about 90 calories, but the same amount of protein and carbs as whole milk.

Milk also contains a smattering of micronutrients as well, namely calcium, magnesium, phosphorus, and vitamins B12 and D (if fortified).

What, then, is so scary about this rather high-protein and nutritious beverage, you wonder?

Well, let’s find out…

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The 6 Biggest Lies and Myths About Milk

If you want to be fat, unhealthy, and disease prone, then you want to drink a lot of milk.

That’s what many people think, at least.

Why, though?

What are the arguments and counterarguments? And what does the scientific literature have to say?

Let’s tackle the big five contentions that account for most of the hand-wringing over milk consumption.

“Milk Causes Weight Gain”

Bodybuilders have been using milk as a “bulking food” for decades now, and for good reason.

If you’re struggling to eat enough calories to gain weight, adding a few cups of milk to your daily meal plan can be an easy way to get the needle moving.

That doesn’t mean milk directly causes weight gain, though, because no food can automagically make you fatter and fatter simply by eating it.

Not milk, sugar, fast food, or anything else.

Remember, no matter what you eat, energy balance dictates what happens to your body weight.

In other words, the real determinant of body weight isn’t food choices but the relationship between energy intake and expenditure.

That’s why Professor Mark Haub was able to lose 27 pounds in 10 weeks eating Hostess cupcakes, Doritos, Oreos, and whey protein shakes.

And why this guy lost 56 pounds in six months eating nothing but McDonald’s, and this guy got into the best shape of his life following a rigorous workout routine and eating McDonald’s every day for a month.

“What about insulin?” you might be thinking. “Doesn’t milk spike insulin levels and thus fat gain?”

Well, yes, milk does raise insulin levels, and insulin does play a role in fat storage, but, again, that doesn’t mean that drinking milk necessarily makes you fat.

Only overeating can cause significant weight gain. Again, energy balance is the key here.

If you eat too many calories of the “cleanest” foods in the world, you’ll gain weight. And if you restrict your calories, you can eat nothing but junk and get leaner.

That’s why studies have repeatedly shown that eating dairy doesn’t cause weight gain, and, in fact, research shows that it can actually help you lose weight faster (for reasons mainly related to satiety and portion control).

Now, another claim often made is that milk contains estrogen-like hormones that can cause weight gain and even feminizing effects in men.

This is partially true.

Yes, milk does contain these types of hormones, but not in large enough amounts to by itself have significant effects in the body.

Case in point:

If you drank one and a half gallons of whole milk in a day, you’d increase your total estrogen levels by no more than 1%.

Moreover, most of of the estrogen-like compounds in milk are broken down during digestion, rendering them physiologically inert.

So, the bottom line is this:

The only way drinking milk can cause you to gain weight is if you’re also regularly eating more calories than you burn.

And even then, remember that it’s the caloric surplus that’s driving your weight up, not the milk.

“Milk Weakens Your Bones”

For years, “everybody knew” that milk was good for your bones.

Now, however, a vocal minority is claiming that it actually weakens them by stripping away calcium.

A study commonly adduced to support this assertion is an analysis of a pool of studies that determined that dairy consumption wasn’t associated with bone health.

(I should note that this study was funded by a vegan organization that has lobbied for the USDA to remove animal products as a food group.)

Milk and dairy detractors have latched onto research like this as definitive proof of milk’s inferiority, but they’re missing the forest for the trees.

When evaluating the scientific research on, well, anything, you can’t simply find a study that you like and put on blinders. You have to look at the rest of the research on the matter and determine which way the literature is leaning.

And when you do that with milk and bone health, the story is crystal clear:

Higher calcium intake is associated with greater bone density, and this includes calcium obtained from milk and dairy.

That doesn’t mean you have to drink milk and eat dairy products to have healthy bones, of course, but it does make it much easier to give your body the calcium it needs.

Another charge often leveled against milk in regards to bone health is that it’s an “acidic” food that, in turn, makes your blood more acidic, which then eats away at your bones over time.

This is utter tripe.

Research clearly shows that no food, milk or sugar or anything else, can significantly impact the pH levels of your blood.

This is good news, too, because if food could do this, you could eat the wrong type of meal and die.

You see, your body must regulate its blood pH very closely, much like temperature, and there’s very little wiggle room.

This is one of the stomach’s primary functions, actually–it uses various chemicals to ensure that everything that makes it through the processes of digestion is “safe” to be released into the blood.

“Milk Contains Dangerous Hormones”

Most cows are given hormones to increase growth and milk production, including recombinant bovine growth hormone (rGBH) and bovine somatotropin (bST).

These hormones do find their way into the milk that’s on the shelves of your local grocery store, and while that sounds ominous, it’s less of a cause for concern than many people think because the amount is miniscule.

Most of the hormone molecules are destroyed during pasteurization, and many of those that aren’t are broken down during digestion, leaving very little to affect your body and health.

Another milk-related hormone that has people in a tizzy is insulin-like growth factor one, or IGF-1, which has similar effects in the body as growth hormone.

This hormone is naturally present in milk (at extremely low levels), and drinking milk boosts your body’s natural production of it, and these facts are used to link milk consumption to cancer.

This is understandable because cancer is, at bottom, uncontrolled cellular reproduction. Thus, someone with cancer certainly wouldn’t want to do anything to boost IGF-1 levels, but that doesn’t necessarily mean that increasing IGF-1 production always increases the risk of cancer in all people under all circumstances.

This is why scientists haven’t yet established whether elevated IGF-1 levels can increase the risk of cancer or are simply a byproduct of it.

In other words, are we looking at causation or correlation? The literature hasn’t provided a definitive answer yet.

It’s also worth noting that IGF-1 levels are generally correlated with your total protein intake, which is why even plant proteins raise IGF-1 levels (soy, for example, even more than milk).

So by the “more IGF-1 = more cancer” logic, a high-protein diet would be far “riskier” than moderate milk consumption. We know there’s no credible evidence that this is the case, however.

Additionally, while research has shown that people who eat more dairy may have a slightly higher risk of certain cancers, most studies show that people who drink more milk have the same or a lower risk of cancer than people who eat less dairy.

The most likely reason for the discrepancy is confounding factors related to lifestyle, like smoking, inactivity, and poor diet, that are known to increase the risk of cancer.

“Milk Is Too Processed to Be Healthy”

If you’re to listen to the quack doctors and “nutrition experts” du jour, food processing of any and all kinds is harmful.

This is silly, and whenever someone tars a broad category or discipline with the same brush like this, alarm bells should start sounding in your head.

Yes, there are types of processing that produce unhealthy foods (oil hydrogenation, for example), but in many cases, processing makes foods safer, tastier, and more nutritious.

In the case of milk and all other dairy products, they go through a variety of steps before they’re deemed ready to eat, with the big ones being pasteurization, homogenization, and fortification.

• Pasteurization is the process of heating milk to 161 degrees (F) for 15 seconds. This kills any unwanted bacteria, ensuring the milk is safe to drink and lasts longer on the shelf.
• Homogenization is the process whereby fat globules are broken into smaller ones and evenly dispersed throughout the milk. This is done to keep the fat from separating from the rest of the liquid and is usually accomplished by forcing the milk through small holes.
• Fortification is the process of adding vitamins and minerals into the milk to make it more nutritious. Vitamin D is the most common nutrient added, but calcium and omega-3 fatty acids are also often included.

Despite the obvious benefits of these processing methods, many health-conscious people have come to believe that completely unprocessed (raw) milk is better for their bodies.

There’s a valid argument to be made here.

Because it’s not pasteurized, raw milk contains more “good” bacteria that support gut health, but there’s a downside, as well: raw milk also contains more “bad” bacteria that can cause sickness.

Raw milk advocates will point out that the risk of getting sick from harmful bacteria present in raw milk is low, which is true, but it’s still much higher than with pasteurized milk. According to CDC data, raw milk is responsible for 71% of the cases of people getting sick from drinking milk.

Another attack on pasteurization is the claim that it removes most or all of the beneficial nutrients naturally found in milk.

This is an exaggeration.

While it’s true that pasteurizing milk does downgrade its nutritional value, this shouldn’t impact the overall nutritiousness of your diet.

The reality is unless you’re getting the majority of your daily calories from milk (which would be stupid), the nutritional difference between raw and pasteurized milk will have no bearing on your health.

Either way, it’ll provide you with an abundance of calcium, and  you’ll still need to eat generous amounts of fruits and vegetables if you want to get adequate amounts of the micronutrients that your body needs to function optimally.

“Milk Is Full of Pus, Blood, and Somatic Cells”

Mmmm…pus, blood, and somatic cells…

This one has really caught on because, well, it sounds disgusting.

It’s also misleading, and to understand why, we have to review how milk is collected from cows.

Most dairy cows are hooked up to mechanized devices for milking that connect hoses to the udders to suck out the milk.

While these machines are able to collect milk faster than people can, they also cause many cows to get an infection called mastitis, which results in painful swelling in their udders.

This, in turn, triggers an immune response in the cows, which includes the increased production of somatic cells to fight off the infection. This does affect the milk, which is why cows with infections produce milk with higher levels of somatic cells than healthy ones.

Furthermore, when somatic cell count is up due to infection, white blood cell count is going to be up, too, which is one of the main constituents of pus.

Thus, the claim that milk contains somatic cells and pus, which, we’d assume, isn’t good for our health.

Well, first of all, milk never contains pus, but white blood cells. “Pus” was chosen for the purposes of propaganda, though, because it conjures nauseating images, whereas “white blood cells” sounds benign.

Moreover, the FDA maintains strict standards for testing for milk for somatic cells and any contaminated batches must be destroyed. Fines are also levied on farmers who consistently produce milk with unacceptable somatic cell counts.

Now, as far as blood in milk goes, it’s more or less the same story.

Small amounts of blood can get into the milk if the cow’s udder is bruised or infected or if it’s harvested after birthing a calf. This is handled in the same way as milk contaminated with somatic cells, though:

If it contains significant amounts of blood, it’s thrown out.

So, while it’s fair to say that milk that comes from healthy cows is “better” (preferred, really) over milk from sick cows, it’s disingenuous to say that all milk contains byproducts of sickness that can, in turn, make us sick, too.

The Bottom Line on Milk and Your Health

Many health and fitness “experts” love to demonize foods.

They love to give people scapegoats, panaceas, and quick-fix solutions because, well, it works.

That’s why fad diets are the order of the day, and why so many people think they should avoid so many of the foods that they like, like sugar, meat, milk and dairy, and many others.

Most of this is manufactured hysteria to sell pills, powders, and diet and workout programs.

A “healthy” diet is far more flexible than you’ve been led to believe, and it can include more or less anything that you like to eat, including, well, sugar, meat, and milk and dairy.

For milk’s part, it’s an inexpensive source of macro- and micronutrients, and is perfectly healthy when included as a part of a balanced diet.

Despite claims to the contrary, it doesn’t cause weight gain or cancer, it doesn’t degenerate your bones, and it doesn’t contain unhealthy amounts of hormones, pus, or blood.                  

What’s your take on whether or not milk is bad for you? Have anything else you’d like to share? Let me know in the comments below!