This article represents part 3 of a series on how insulin has been unfairly demonized by many in the nutrition field. If you have yet to read the first few parts, you can read Part 1 here, and you can read Part 2 here. In this article, I will discuss how dairy products are among the most insulinemic foods out there, yet do not promote fat or weight gain, which pokes holes in the hypothesis that carbohydrates drive fat accumulation through insulin secretion.
Dairy Products Are Insulinemic Yet Don't Promote Weight Gain
One of the premises of individuals like Gary Taubes is that carbohydrates stimulate fat accumulation by stimulating insulin secretion. I've already shown how this premise is flawed in the last two parts of my series. Namely, I showed how protein also stimulates insulin secretion (sometimes as much as carbohydrate) yet does not promote weight or fat gain. I also showed how the drug exenatide restores rapid-phase insulin secretion in diabetics yet promotes weight loss.
If the carbohydrate/insulin hypothesis were true, then we would predict that foods that are extremely insulinemic would be uniquely fat promoting. What many people do not realize is that dairy foods are among the most insulinemic foods out there. In fact, they create much greater insulinemic responses than you would expect based on their carbohydrate content. Not only that, but lactose, the primary carbohydrate in dairy foods, is actually low glycemic and produces slow rises in blood sugar (lactose has a glycemic index of 46 compared to white bread which is 100). In fact, the glycemic index of many dairy products is quite low, with full-fat milk at 39, skim milk at 37, ice cream at 51, and fruit yogurt at 41.
Despite the low blood sugar responses, dairy products create very large insulin responses. For example, in one study, dairy products created similar or greater insulin responses than white bread, despite the fact that the blood sugar response for some of the dairy products was 60% lower than the white bread. In this study, the researchers compared the glycemic and insulinemic responses between white bread, a low gluten/lactose mixture, a high gluten/lactose mixture, cod with added lactose, milk, whey protein with added lactose, and cheese with added lactose. All of the conditions contained 25 grams of carbohydrate and 18.2 grams of protein, except for the white bread and low gluten/lactose mixtures, which contained 25 grams of carbohydrate and 2.8 grams of protein. Thus, lactose was the carbohydrate in all of the conditions except for white bread.
When you look at the insulin area-under-the-curve (AUC) for the various conditions, you can see that the dairy products actually created greater insulin responses than the white bread, despite having similar amounts of carbohydrate:
Insulin response of dairy foods compared to white bread
It is obvious that it is not the lactose that is responsible for the greater insulin response, because the gluten/lactose and cod/lactose mixtures resulted in similar or lower insulin responses to white bread.
The blood sugar response was also not responsible for the greater insulin response. In fact, the blood sugar response was lower in all of the conditions compared to the white bread, with the milk creating the lowest blood sugar response yet 3rd highest insulin response:
Blood glucose response to dairy foods compared to white bread
The insulinogenic index, which relates the amount of insulin secretion to the blood glucose response, was significantly higher in the dairy products, indicating that the dairy products stimulated much greater insulin secretion that you would expect based on the blood glucose response:
Insulinogenic index of dairy products compared to white bread
This is not the only study to show the insulinemic effects of dairy products. I showed in my previous article how whey protein, a dairy protein, created the highest insulin response compared to non-dairy proteins. In a study on type 2 diabetics, the inclusion of whey protein in a meal increased the insulin response by 31-57%, while the blood glucose response was reduced by up to 21%. In another study, the addition of 400 mL of milk to a bread meal increased the insulin response by 65%, despite the fact there was no change in the blood glucose response. In this same study, the addition of 200 or 400 mL of milk to a spaghetti meal increased the insulin response by 300%; again, there was no change in the blood glucose response. In fact, drinking milk with the spaghetti meal created an insulin response that was similar to white bread.
Here's the results of another study showing the glycemic and insulinemic indexes of milk compared to white bread:
Why Does Dairy Stimulate So Much Damn Insulin?
It is clear that dairy products stimulate large amounts of insulin secretion, as much or more than white bread. One of the reasons dairy products create large insulin responses is due to their amino acid content. In fact, the postprandial insulin response from dairy products correlates with the rise in branched chain amino acids leucine, valine, and isoleucine. I already pointed out in part 1 of this series how leucine will directly stimulate your pancreas to produce insulin.
Another reason that dairy products stimulate so much insulin secretion is their effects on a hormone called glucose-dependent insulinotropic polypeptide (GIP). Like GLP-1 which I wrote about in part 2 of this series, GIP is an incretin. This means that it is a hormone produced by your intestines that stimulates insulin secretion. Dairy products stimulate increased production of GIP. In the study I discussed earlier which compared whey, milk, and cheese to white bread, whey and cheese resulted in 21-67% greater GIP responses than white bread:
Glucose-dependent insulinotropic polypeptide (GIP) response to dairy foods compared to white bread
The above data illustrates one of the problems with the carbohydrate/insulin hypothesis...it assumes that carbohydrate is the primary stimulus of insulin secretion. However, it is clear that amino acids and incretins play significant roles in insulin secretion as well. And as I pointed out in part 1 of this series, the blood sugar response of a food only explains 23% of the variation in the insulin response. Thus, a lot more goes into insulin secretion than the blood sugar response from eating carbohydrate.
Dairy and Weight Gain/Loss
It is clear that dairy products are extremely insulinemic, moreso than many high carbohydrate foods. Thus, if the carbohydrate/insulin hypothesis were true, then we would predict that a diet high in dairy products should promote weight and fat gain. However, studies fail to show any relationship between dairy product intake and weight gain. For example, there is no relationship between intake of dairy products and BMI in Japanese women. In U.S. men, there is no relationship between an increase in dairy consumption and long-term weight gain. In perimenopausal women, high intakes of dairy products are actually inversely associated with weight gain (i.e, higher dairy product intakes are associated with less weight gain).
While these are observational studies, the results from controlled studies on animals and humans are similar. In fact, animal studies show less weight gain when they are fed dairy products. In mice, yogurt supplementation results in less weight and fat gain than controls on isocaloric diets. In another study, transgenic mice lost weight on energy restricted diets. The mice were then allowed to eat ad libitum (i.e., as much as they felt like). The mice fed dairy products regained less fat and weight during refeeding. In a third study, the intake of dairy products, but not a calcium supplement, decreased weight gain and body fat in mice fed a high-fat diet. In a fourth study, dairy protein attenuated fat gain in rodents fed a high-fat, high-sugar diet. In a fifth study, a dairy diet attenuated weekly weight gain in Sprague-Dawley rats.
Of course, these are animal studies. What about humans? In one study, low-fat dairy products did not promote weight gain, while high-fat dairy products did. Hmmm, could it be that the weight gain in this study was simply caused by excess calories and not insulin? In another study, increased intake of dairy products did not affect body composition. In a third study, increased intake of dairy products did not impair weight loss. In a one-year study, increased intake of dairy products did not affect changes in fat mass. In a 6-month follow-up to this study, high dairy product intake predicted lower levels of fat mass. In a 9-month study, increased intake of dairy products did not affect weight maintenance, but the high dairy group exhibited evidence of greater fat oxidation.
Why Am I Not Fat?
My own personal experience with dairy fits right in with the science. I consume a lot of dairy and have for many years. I go through 2-3 gallons of milk per week. I also go through a lot of Greek yogurt, cottage cheese, regular cheese, and whey protein. I have some type of dairy with just about every meal. Thus, I have large amounts of insulin flowing through my body pretty much all day. If insulin was truly the fat-promoting, weight-gaining hormone that some have made it out to be, then I should be obese by now. Yet, I am not...not even close.
Not only that, but the people who think insulin makes you hungry, that would imply that I should be starving all of the time with all of the insulin that is flowing through my body all day. Yet, I'm not.
Got Milk? Got Insulin!
The evidence is overwhelming that dairy products do not promote weight gain, and they actually inhibit weight gain in animal studies. This is despite the fact that dairy products produce very large insulin responses, as much or greater than many high carbohydrate foods. Thus, it is clear from this article, as well as my previous articles, that the carbohydrate/insulin hypothesis is incorrect. Insulin is not the criminal in the obesity epidemic; instead, it is an innocent bystander that has been wrongly accused through guilt by association.
Click here to read part 4 of my series, where I address the misconception of how insulin regulates blood sugar.
James, Good points about dairy being insulinogenic, and yet not fattening by itself. But I think you are missing something important here: Advocates of the carbohydrate/insulin hypothesis typically do not claim that insulin by itself induces fat storage; glucose must also be present. Taubes quotes Edgar Gordon on p. 392 of Good Calories, Bad Calories as follows: the storage of fast, and therefore the production and maintenance of obesity, cannot take place unless glucose is being metabolized. Since glucose cannot be used by most tissues without the presence of insulin, …obesity is impossible in the absence of adequate tissue concentrations… Read more »
There also might be an issue of the time horizon. What happens after one meal might not be indicative of what happens after years of exposure.
There have been several diet studies that have shown low-carb diets lower fasting insulin levels overtime better than low fat diets.
This is my favorite:
http://www.nutritionandmetabolism.com/content/3/1/7
There also might be an issue of the time horizon. What happens after one meal might not be indicative of what happens after years of exposure. If years of exposure to an insulinemic diet were a problem, then years of exposure to dairy products would be a problem as well. Yet the scientific data does not reveal any problem. There have been several diet studies that have shown low-carb diets lower fasting insulin levels overtime better than low fat diets. The vast majority of the studies show lower fasting insulin levels because of the greater weight loss with the low… Read more »
Advocates of the carbohydrate/insulin hypothesis typically do not claim that insulin by itself induces fat storage; glucose must also be present. This is still not consistent with the scientific data. First, dairy products are rarely consumed by themselves. Milk, yogurt, and cheese are typically consumed with glucose-elevating foods. Yet we know from controlled human and animal trials that dairy does not cause weight gain despite being consumed along with glucose-elevating foods. Second, as I highlighted in this article, this stance reveals an inconsistency in the carbohydrate/insulin hypothesis. On one hand, advocates of the hypothesis claim that the primary way in… Read more »
“In fact, full-fat dairy (which will not increase the insulin response any more than low-fat dairy) has been found to cause weight gain, while low-fat dairy does not.”
In one study on a grand total of 45 volunteers? Sorry, but when you look at more data you see the opposite is more likely true: full-fat dairy is associated with a lower risk of obesity.
http://www.npr.org/blogs/thesalt/2014/02/12/275376259/the-full-fat-paradox-whole-milk-may-keep-us-lean
Donjoe, The article you link to cites observational studies, which cannot established cause/effect. The data I linked to was a randomized controlled trial, which always takes precedence over observational data. If you find statistical significance with 45 volunteers, that is not a fault of sample size, as it is often more difficult to find statistically significant results with smaller sample sizes. In fact, there is nothing wrong with a sample of 45 if the sample is adequately randomized and is representative of the population being studied. Note that I am not saying that full-fat dairy is bad to consume. I… Read more »
But that is exactly what the low-carb camp claims its diets do, among other things: help control calories, albeit without having to count them. By shifting away from carbs you open up the fat stores to be used, which also influences the hunger signal cycle, and at the same time you eliminate the sugar cravings that would make you snack when you’re not hungry, just for the sake of feeling a pleasant taste. Just because somebody compared low-fat and full-fat dairy in a laboratory setting with controlled consumption of food that did not allow caloric self-regulation doesn’t mean that self-regulation… Read more »
By shifting away from carbs you open up the fat stores to be used, This is false, and it is not how low carb diets work. It is an energy deficit that allows fat stores to be used for fuel, not going low carb. One can be low carb yet not lose fat because any fatty acids released from stored triglycerides are simply repackaged back into triglycerides. Low carb diets work because of the satiety benefit of the high protein intake. In fact, there is data showing no difference in fat loss when a high protein, low fat, high carb… Read more »
“This is false, and it is not how low carb diets work.” 1. No it’s not, it’s been a well-known fact of biochemistry for more than 50 years. “Decreased lipolysis – forces reduction in conversion of fat cell lipid stores into blood fatty acids; lack of insulin causes the reverse.” http://en.wikipedia.org/wiki/Insulin#Physiological_effects 2. Yes it is how low-carb diets work, via caloric self-regulation, which creates the caloric deficit you’re talking about. That’s what its proponents told me it does and that’s what I saw it do in my case, no calorie counting required. “You obviously did not read the study that… Read more »
1. No it’s not, it’s been a well-known fact of biochemistry for more than 50 years. “Decreased lipolysis – forces reduction in conversion of fat cell lipid stores into blood fatty acids; lack of insulin causes the reverse.” http://en.wikipedia.org/wiki/Insulin#Physiological_effects You obviously did not read what I wrote. Let me say it again: One can be low carb yet not lose fat because any fatty acids released from stored triglycerides are simply repackaged back into triglycerides. You see, you are making the mistake of confusing lipolysis with fat loss. They are not the same thing. Lipolysis only refers to the release… Read more »
“Low carb diets work because of the satiety benefit of the high protein intake. In fact, there is data showing no difference in fat loss when a high protein, low fat, high carb diet is compared to a high protein, high fat, low carb diet.”
You should know how this works by now: link to study or it didn’t happen.
This study showed no difference in weight loss when a low carb diet was matched with a high carb diet, when protein was matched. This study showing that a high protein intake caused a spontaneous reduction in calories by over 1,000. Combining high protein with low carb only reduced calorie intake by an additional 168 calories beyond the high protein/moderate carb intake. The slightly greater weight loss in the low carb condition was due to a lower calorie intake, more fat mass loss, more lean mass loss, and more body water loss. The slight boost in appetite reduction was likely… Read more »
OK, but even if it were true that HP is what drives the caloric restriction (via appetite suppression) that gives LC diets their effectiveness, it would still be highly contentious to recommend LCHP over LCHF knowing that HP is also associated with higher mortality, as shown in e.g. http://www.cell.com/cell-metabolism/fulltext/S1550-4131(14)00062-X
There’s serious problems with the conclusions to that paper that you reference. Dr. Stuart Phillips outlines them here:
https://twitpl.us/t/s7eb
Well, thanks for the debate – the more I look at this the more I have to agree that protein probably plays an important role in the effectiveness of LC diets. I’ve looked over 10-20 abstracts of studies promoted by the LCHF crowd and have yet to see one that supports LCHF specifically rather than being equally easy to interpret as proof of the effectiveness of LCHP. E.g.: “The 4 study diets used in our study differed significantly in composition beyond carbohydrate content. Protein, fat, and saturated fat followed a continuum across diets, inverse to carbohydrate content. In a series… Read more »
Hi, I’m new to the site as well, but it looks like you have some interesting reading here and I look forward to delving into it. As for dairy and insulin, though, I don’t see where you can say that because dairy causes an insulin rise but weight gain does not (always) go along with it, that that proves that insulin is not the main culprit as far as fat gain. This makes sense in that the purpose of dairy is to grow immature animals to the stage where they can start getting enough nutrition on their own to become… Read more »
As for dairy and insulin, though, I don’t see where you can say that because dairy causes an insulin rise but weight gain does not (always) go along with it, that that proves that insulin is not the main culprit as far as fat gain. Jennifer, If this was the only piece of evidence that I used, then you would have a point. However, there is a concept known as the convergence of evidence. In this case, I gave a variety of reasons as to why the carbohydrate/insulin hypothesis fails. When you have such a variety of examples and observations… Read more »
I was thinking too that insulin and leptin are strongly connected, insulin is a satiaty hormone so is leptin (there is still a lot they do not know about leptin) but you can get fat for a lot of reasons, poor quality nutrients if your famine sensitive (genetically speaking) low nutrients like vitad3 for glucose tolerance (fat cells are very good sponges for sugar that is stuck in the circulation to long and anyone who knows sugar is very oxidative and damaging to cells if they stick to it and oxidize) fat cells store more then just fat, they store… Read more »
I’m new to your blog and this was a fascinating read for me. I have a very unscientific mind, so please excuse the following question which seems quite logical to me but may be way off: If whey or dairy ‘rev up’ insulin production while at the same time keeping BG low, would it help a pre-diabetic like me to consume some dairy along with carbs to help raise insulin to counter BG spikes? And I just have to ask this, James: Why are you consuming so much dairy – and low-fat at that! I would understand it if it… Read more »
James, your excellent series has been a great revelation on the workings of insulin. I too am a dairy fan, but I use only raw Jersey milk with some made into kefir, plus some cheese (usually goat cheese lately). I’d be curious to see a post about your views on raw vs pasteurized/homogenized dairy and whole vs low-fat dairy (forgive me if you’ve already covered these topics since I’m new to your blog and haven’t looked at earlier posts yet).
Bryan,
Thanks for the comment. I don’t have any posts on the topics you mentioned but I’ll keep them in mind for future topics.
“Why Am I Not Fat? My own personal experience with dairy fits right in with the science. I consume a lot of dairy and have for many years. I go through 2-3 gallons of milk per week. I also go through a lot of Greek yogurt, cottage cheese, regular cheese, and whey protein. I have some type of dairy with just about every meal. Thus, I have large amounts of insulin flowing through my body pretty much all day. If insulin was truly the fat-promoting, weight-gaining hormone that some have made it out to be, then I should be obese… Read more »
I bet you don’t consider it as such proof (which I’ll agree to of course)… so your argument makes no sense at all. People using isolated examples (or worse, a personal isolated example) to backup their point, while on the other hand bashing the logic of others, are highly suspect in my book. Franck, you would have a point if all I used was an isolated example, and nothing else. Anecdotal evidence, on its own, is not good evidence. However, my personal testimonial was nothing more than an additional point to the large body of scientific research that I presented… Read more »
“large body of scientific research that I presented on how dairy does not increase weight gain risk”
Last time I looked outside dairy was turning a 80lb calf into a 2000lb monster in as little as 6-9mnths………..
Last time I looked the consumption of milk by a calf is not relevant to the consumption of milk by a human adult.
If you have research to show that milk consumption directly causes weight gain, then please provide it. I’ve already provided plenty of scientific references showing the opposite.
the cows growth is determined by hormones not hte source of the food, it is how your body allocates the nutrients it receives which is geneticlally determined. horses and cows and goats can get fat on grass alone (should know owned horses and goats before) yet it is a low carb high fiber food, and no fat either. it is how the body is designed to use the nutrients it gains and how it reacts to overnutrtion or under nutrtion.
Good post, James. I must say, nevertheless, that insulin is part of the problem, not the only one. Most trials showing the insulin response to a meal are just that, after 1 meal, in particular “healthy” individuals. You would expect that postprandial insulinemia after a calorie restricted diet high in carbohydrates or high protein/fat/LC would be practically the same (because as you imply, protein stimulates insulin as much as carbs). However, this is not the case. You know that insulin stimulation by protein/aminoacids is not equal as stimulation by carbs. The other issue is BG. While the insulin response can… Read more »
Lucas, Most trials showing the insulin response to a meal are just that, after 1 meal, in particular “healthy” individuals. One of the trials I referenced was on obese people. And, in fact, the insulin response is exaggerated in most obese people, even with a high protein, low or moderate carb meal. Yet, we know that high protein intakes are beneficial for weight loss for obese people. This is why it is misguided to focus on insulinemia. (because as you imply, protein stimulates insulin as much as carbs). I never made such an implication. I said protein CAN stimulate insulin… Read more »
In my experience, dairy can be “fattening” in a low carb context, but not for the typical insulin (ir)rationale. Even if one is eating fatty meats, chicken with skin, bacon, etc., these foods tend to be self-limiting for most people. There are some people who may eat bacon grease or all of the drippings from a fatty burger, but animal fats and oils are not particularly palatable to most people. For example, I use 80-85% ground beef because I like the flavor and texture of the finished product. But if I’m browning it for a chili, I drain excess fat… Read more »
CarbSane,
I think you’ve hit on the concept of energy density here. Many high-fat dairy products (like whole milk and cheese) are extremely energy dense. On top of that, you’re dealing with liquid calories versus solid calories in terms of the full-fat milk, which will not be as satiating. So in this sense, I would agree that dairy can promote weight gain. Myself, I use low fat and non-fat dairy products so this tends not to be an issue for me.
Liquid calories have been shown in many studies to be more satiating.. the expansion and subsequent retraction of the stomach when consuming solids increases the ghrelin response causing hunger earlier and stronger.
Liquid calories have not been shown in many studies to be more satiating. If you have the references to back up your claims, please provide them.
Also, the expansion and retraction of the stomach does not increase the ghrelin response. Also, alterations in ghrelin within a physiological range tend not to be associated with changes in hunger.
whole milk is very satiating for me, if I juice my own fruit like oranges and pineapples apples etc it is very satiating for me. there is more to satiaty then fiber in food, there is protein, fats, some carbs, vita/min. phytochemicals etc. dont know where they got the idea somehow liquid caloires are worse then solid foods for satiaty and appetite control, I always thought appetite control originates in the brain when it gets the signals your adequatly fed so it shuts down desire to eat.
so much food for thought. I’ll avoid the puns for now. I really hope you’re angling all this work to be re-useable, angling toward ending up with something publish-able to compete against the pseudo science in the diet industry. For a long time I’ve been favoring the more expensive and horrid-tasting casein products over whey products, reasoning that casein’s slower-release protein would be better for hunger control, and partly this had to do with insulin control, (whey releasing more insulin, so preference goest to casein). This series on insulin is making me rethink my approach – the only argument left… Read more »
Sam,
The research definitely supports slower gastric emptying times to help with appetite. In fact, there was a recent study published that compared casein to whey and satiety was superior in the casein condition.
I thought your comment was pretty sweet … but when I went to hunt down the study you’re talking about I’m finding a lot of the opposite?
Very very possible I’m misunderstanding the studies though.
This one reviews studies about appetite and protein sources:
http://ajcn.nutrition.org/content/87/5/1558S.full
And these are casein vs whey for appetite studies it mentions:
http://www.ncbi.nlm.nih.gov/pubmed/12575908?dopt=Abstract
http://www.ncbi.nlm.nih.gov/pubmed/11237351?dopt=Abstract
Hi, Shane, One of the studies you linked to used a breakdown product of casein, rather than casein itself. The other study did show superior subjective suppression of appetite with whey. While studies are conflicting in this area, it should be noted that appetite is quite a complicated beast, and the impact of a particular protein on appetite can vary from one study to another just due to differences in study methodology. In other words, was a preload consumed? If so, what was the type of preload? How was appetite assessed? Did they measure ad libitum food intake at a… Read more »
Krieger, you’ve done it again. You’ve completely thrown my head into a spin. Very nice and now I really understand more clearly the effect of carbs and diet. From what I gather, it’s not ingesting of carbs, but rather making sure I get the right amount of calories that are sustainable. Better carbs equals more satiety? More fats and better proteins to help the process? Very Nice! Thank you so much, because I am following a low carb diet but high amounts of protein and fats. My losses are due to calorie reduction and satiety, because I do feel full… Read more »
Hey, Jason! Thanks for stopping by and glad you like my articles! Hope all is well with you down in the big state of Texas!
Mr. Krieger, First let me thank you for sharing such excellent content. It is a genuine honor to stop by and read your work. While I would still not make any sort of wild claims about promoting weight gain, per se, the fact that this series is on insulin did make me want to ask your general take on a somewhat related topic. With wide variation in individual sensitivities to various foods, and coupled with the often high stress nature of modern life (both beyond our control and oftentimes even more from self-imposed stress) is it possible that dysfunctional insulin… Read more »
Giuseppe, Thank you for your comment and I’m glad you like my work! There is some evidence that stress-induced cortisol secretion can induce insulin resistance, which, in turn, would then lead to appetite dysregulation. There is also evidence that some people are stress “hyperresponders” in terms of cortisol while others are not, and also that some people overeat in response to stress while others do not. I would highly agree with you that the high stress nature of modern life certainly is a contributor to the obesity epidemic, and there is sufficient scientific data to support that. There is also… Read more »
As far as the stress in modern life goes, I do believe that taking time out in nature, and not to mention taking time to do nothing (not constantly using your cell phone etc. when you got nothing else to do) can help.
Take a look at this review, and pleas give me your thoughts, James; http://www.ncbi.nlm.nih.gov/pubmed/19826546
Fredrik,
Interesting paper. There are certainly challenges in interpreting some of the existing data (i.e., correlation versus causation) and the quality of some of the studies referenced, but I certainly agree with you that occasional time-outs, whether in nature or just taking a break, certainly are beneficial.