From Whole9, as a preface to their Manifesto series (check out Dallas & Melissa' work here

As we wrote in It Starts With Food, “We have a theory about food that directly influences the rest of this book. The food that you eat either makes you more healthy or less healthy. Those are your options.”

Of course, we spend the rest of the book explaining why a concept that sounds so simple is not that simple at all in practice. That’s why our Good Food recommendations are based on not just one foundation, but a combination of three:

Based on the science as we understand it today, and our vast clinical experience with the tens of thousands of people who have completed our Whole30 program, we make some general recommendations as to which food groups may make you less healthy. The discussion of dairy*, however, has no simple, black-and-white answers. There are many functional components of dairy that, depending on the source and the individual consuming it, could be highly problematic, generally benign, or even beneficial.

Below, we’ll outline the basics of our case against regular consumption of dairy, based on the potential downsides. But until you undertake your own self-experiment (via the Whole30) for yourself, you’ll never know for sure how consumption of dairy products are affecting how you look, how you feel, andyour quality of life.

*While the vast majority of dairy consumed in the United States is from cows, you can also apply these concepts to sheep or goat milk.

Milk: The Perfect Food (in Context)

Milk is an excellent source of energy and building blocks to rapidly grow mammals that are too young to eat adult food, such as grass (cows) and a wide range of plants and animals (humans). Until a mammal’s digestive system has completely developed and it can eat whole food, mother’s milk supplies optimal nutrition.

But mother’s milk is not just an inert supply of carbohydrate, protein, and fat—though it contains significant amounts of all of those macronutrients. Milk is an energy-dense hormone-delivery system–a blend of bioactive substances that not only promote aggressive growth of a very young mammal (doubling or tripling bodyweight in a very short period of time), but also ensure the complete development of the young one’s immune system. In this context, milk is the perfect food, and the perfect messenger.

However, when the biological messages intended for a calf are being received loud and clear by your adult human body, they are far less appropriate—and potentially downright harmful.

Milk Proteins: Casein and Whey

Casein makes up about 80 percent of total milk protein, and acts as a source of amino acid building blocks. In addition, protein sequences embedded in casein’s molecular structure are released during the digestion process and send a message from mother to young. The effects of these potently bioactive “food hormones” from another species on human adults remain largely unknown.

Casein, especially when it comes from aged cheese, also causes a specific type of immune system reaction called a histamine response . Histamine intolerance can cause headaches, GI upset, exacerbations of asthma, and seasonal allergies. It is unclear what percentage of the population has this response, but until you have completely removed all dairy proteins from your diet for a period of time, you won’t know whether or not you are affected.

Finally, casein shares some structural similarities with components of gluten. This means that gluten-sensitive individuals (including those with celiac disease) are less likely to tolerate casein-containing dairy products. Research suggests that at least 50 percent of celiacs are also sensitive to milk.

The other major category of milk protein is whey. Whey is a blend of multiple types of smaller proteins and hormones, including immunoglobulins, insulin, insulin-like growth factor 1 (IGF-1), estrogens, and other growth factors. (Remember, milk is a powerful growth promoter!) For this reason, milk is a highly insulinogenic food, which means that the combination of lactose plus whey dairy proteins causes the release of very large amounts of insulin when consumed.

The remarkably large amount of insulin secreted in response to milk and whey protein intake may prove problematic for those with metabolic syndrome, as in this population, it does not promote a healthy hormonal response. Anyone seeking to improve insulin sensitivity (or avoid becoming insulin resistant) would be best served by avoiding dairy products.

Insulin is not the only potentially detrimental hormone increased by milk. Milk consumption also significantly elevates IGF-1, another powerful growth-inducer. IGF-1 promotes growth in children, but it is also associated with promotion (or indirect facilitation) of various cancers, such as breast, colon, and prostate. Of course, we’re not saying that if you drink milk, you’ll get cancer, but if you’re at high risk, consuming substances that increase the growth of cells, including abnormal cells, seems unwise.

Milk Sugar: Lactose


The carbohydrate component of dairy products can also pose problems. The kind of carbohydrate found in milk is called lactose. While there are not huge amounts present in milk (and some other dairy products have very little because of processing), lactose is an issue for a surprisingly large percentage of people.

If lactose cannot be properly digested, bloating and gastrointestinal upset may result. In addition, consuming even small amounts of lactose may contribute to an imbalance of gut bacteria, promoting dysbiosis. In addition, many people who consider themselves lactose-intolerant (by observing that dairy makes them feel poorly) may have a sensitivity to dairy proteins as well.

Milk Fat: Butter and Heavy Cream

You may have noticed that we haven’t expressed any specific concerns about dairy fat. We consider pastured, organic butter (especially when it’s clarified) and heavy cream as generally healthy choices.

Research studies that compare full-fat dairy with reduced-fat dairy demonstrate better health outcomes with full-fat dairy. This is not an endorsement of whole milk—these benefits are largely due to the health-promoting properties of dairy fat. As one example, pastured, organic butter contains little to none of the protein fractions, growth promoters, or hormones found in milk but has many beneficial compounds including vitamin K2, conjugated linoleic acid (CLA), and even those famous omega-3 fatty acids. You can further ensure butter is a healthy choice for you by clarifying it, thereby removing any of the potentailly problematic milk proteins.

What About Raw Milk, Fermented Dairy, and Calcium?

Proponents of raw milk will say that raw (unpasteurized) milk is a superior choice, since the pasteurization process destroys enzymes (such as lactase) that help digest some components of the milk. However, aside from those issues, all of the other concerns mentioned above still apply to raw milk.

Fermented dairy (such as yogurt or kefir) does have some advantages over regular milk. Since the bacteria in these foods have broken down a significant amount of the lactose and dairy proteins, people generally have greater tolerance for it. The most commonly cited benefit of fermented dairy is its health-promoting bacteria, which help to maintain the balance of gut bacteria. While you can obtain some benefits from consuming these bacteria, the delivery mechanism may still prove imperfect, and individual tolerance varies greatly.

We address the issue of how to maintain strong, healthy bones without consuming dairy in our article,What About Calcium?