In 2012 a popular new blogger named Kris Gunnars at Authority Nutrition wrote a post, "Top 15 Reasons You Are Not Losing Weight on a Low-Carb Diet." Reason #7 was “You’re Eating Too Much Dairy.” Kris said (emphasis mine):
“Another low-carb food that can cause problems for some people is dairy.
Some dairy products, despite being low in carbs, are still pretty high in protein.
Protein, like carbs, can raise insulin levels, which drives energy into storage.
The amino acid composition in dairy protein makes it very potent at spiking insulin. In fact, dairy proteins can spike insulin as much as white bread.
Even though you may seem to tolerate dairy products just fine, eating them often and spiking insulin can be detrimental to the metabolic adaptation that needs to take place in order to reap the full benefits of low-carb diets.
In this case, avoid milk, cut back on the cheese, yogurt and cream. Butter is fine as it is very low in protein and lactose and therefore won’t spike insulin.
Bottom Line: The amino acid composition in dairy proteins makes them spike insulin fairly effectively. Try eliminating all dairy except butter.”
Similarly, Mark Sisson at Mark's Daily Apple wrote his "17 Reasons You're Not Losing Weight" of which #17 is, “You’re Eating Too Much Dairy.” His text is provided below (again, emphasis added by me):
“Some people just react poorly to dairy. We see this time and time again listed in the forums; dairy just seems to cause major stalls in fat loss for a good number of folks. There are a couple speculative reasons for this. One, folks coming from a strict paleo background may not be acclimated to the more relaxed Primal stance on dairy. Reintroducing any food into the diet after a period of restriction can have unintended consequences on body composition. Two, dairy is insulinogenic, which is why it’s a popular post-workout refueling tool for athletes. Does a non-strength training PBer need to drink a few glasses of milk every day? Probably (definitely) not.”
What caught my interest was the conjunction of dairy protein to insulin secretion. Mark further elucidates that in another post, “Dairy and Its Effect on Insulin Secretion (and What It Means for Your Waistline),” Here’s an excerpt:
“Cream and butter are not particularly insulinogenic, while milk of all kinds, yogurt, cottage cheese, and anything with casein or whey, including powders and cottage cheese, elicits a significant insulin response. In one study, milk was even more insulinogenic than white bread, but less so than whey protein with added lactose and cheese with added lactose. Another study found that full-fat fermented milk products and regular full-fat milk were about as insulinogenic as white bread.”
Finally, footnote #7 in Kris Gunnar’s post takes you to a study by scientists from the highly respected universities in Malmo and Lund, Sweden and Copenhagen Denmark. Again, the emphases are mine.
“Glycemia and insulinemia in healthy subjects after lactose-equivalent meals of milk and other food proteins: the role of plasma amino acids and incretins.
Background: Milk products deviate from other carbohydrate-containing foods in that they produce high insulin responses, despite their low GI. The insulinotropic mechanism of milk has not been elucidated.
Results: A correlation was found between postprandial insulin responses and early increments in plasma amino acids; the strongest correlations were seen for leucine, valine, lysine, and isoleucine.
Conclusions: It can be concluded that food proteins differ in their capacity to stimulate insulin release, possibly by differently affecting the early release of incretin hormones and insulinotropic amino acids. Milk proteins have insulinotropic properties; the whey fraction contains the predominating insulin secretagogue.”Okay, this is getting a little heavy, but you get the point. If not, go back and read this post again, seriously. If you are wondering why you are not losing weight on a low-carb diet, milk protein could be the reason – particularly, but not exclusively the whey protein fraction. Butter (ideally from grass fed cows) and heavy cream, may be excepted, but here’s the takeaway: “…milk of all kinds, yogurt, cottage cheese, and anything with casein or whey, including powders and cottage cheese, elicits a significant insulin response.” And “elevated insulin… drives fat storage.”