This link from Janet (JEY100), a helpful member on a popular Active Low-Carber Forum led me to a popular new blogger named Kris Gunnars and his blog Authority Nutrition. The link was to his "Top 15 Reasons You Are Not Losing Weight on a Low-Carb Diet." Reason #7 was “You’re Eating Too Much Dairy.” This is what 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 (7, 8).
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.”
The low-carber forum blogger also provided a link to Mark Sisson’s Mark's Daily Apple with 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 in both of these posts, obviously, was the reference to insulin secretion with respect to protein and dairy protein in particular. My interest was further piqued when I read Kris’s “very potent” hyperlink above, which as it turns out is to Mark’s elucidation of his “tip.” That excellent post by Mark, “Dairy and Its Effect on Insulin Secretion (and What It Means for Your Waistline),” is too long to copy here, so I’ll just provide an excerpt (all my emphasis):
“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 (PDF), milk was even more insulinogenic than white bread, but less so than whey protein with added lactose and cheese with added lactose. Another study (PDF) found that full-fat fermented milk products and regular full-fat milk were about as insulinogenic as white bread.”
Do you see where I’m going with this? Finally, footnote #7 in Kris Gunnar’s post takes you to this study by scientists from the highly respected universities in Malmo and Lund, Sweden and Copenhagen Denmark. Again, the underlining is mine.
“Glycemia and insulinemia in healthy subjects after lactose-equivalent meals of milk and other food proteins: the role of plasma amino acids and incretins1,2,3
Authors: 1. Mikael Nilsson, 2. Marianne Stenberg, 3. Anders H Frid, 4.Jens J Holst, and 5.Inger ME Björck
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.
Objective: The objective was to evaluate the effect of common dietary sources of animal or vegetable proteins on concentrations of postprandial blood glucose, insulin, amino acids, and incretin hormones [glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1] in healthy subjects.
Design: Twelve healthy volunteers were served test meals consisting of reconstituted milk, cheese, whey, cod, and wheat gluten with equivalent amounts of lactose. An equicarbohydrate load of white-wheat bread was used as a reference meal.
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. A correlation was also obtained between responses of insulin and GIP concentrations. Reconstituted milk powder and whey had substantially lower postprandial glucose areas under the curve (AUCs) than did the bread reference (−62% and −57%, respectively). Whey meal was accompanied by higher AUCs for insulin (90%) and GIP (54%).
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 thick, but you get the point, I hope. If not, go back and read this link by Mark Sisson, 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. That insight sure resonated with me.