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Does Butter Raise Insulin And Make You Fat? The Low-Carb Experts Respond To This Claim

Posted Apr 07 2010 1:59pm

One of the attractions of a healthy low-carb diet for many people is the ability to consume butter again. For years we’ve been told by groups like the American Heart Association that saturated fats like butter will raise your cholesterol (which is true–HDL “good” cholesterol goes WAY UP when you consume butter!) and that we should be choosing “better” alternatives like margarine and olive oil instead. We’ve all heard the heart health argument, but recently a cardiologist blogger in the low-carb community brought up a rather intriguing theory that perhaps the reason some low-carbers begin to struggle on their low-carb lifestyle is because of what he describes as “butter’s unusual ability to provoke insulin responses.”

Respected blogger and physician Dr. William Davis from “The Heart Scan Blog” has been putting out quality information and nutrition and health over the past four years and we owe him a great debt of gratitude for the amazing work he has been doing to promote the message of less carbohydrate in the diet as a means for keeping our hearts healthy. He’s championed the CT scan for measuring plaque buildup in your coronary arteries as well as making sure you are getting adequate Vitamin D3 levels in your body and proper thyroid function. He literally is a one-man machine of information that is worth paying attention to. That’s what made his March 19, 2010 column entitled “Butter and Insulin” so perplexing to me when I read it.

Dr. Davis cites this September 2008 study published in the American Journal of Clinical Nutrition as his evidence for believing there is up to a triple insulin response in those people who consume butter in their diet. And, of course, we all know that the higher the insulin levels in the body, the faster you will gain stored body fat. So this one study by a researcher named Dr. Sergio López led Dr. Davis to make the following assertion in his blog post.

Fat, in general, does not make you fat. But butter makes you fat.

Now I don’t know about you, but when I hear a cardiologist that I greatly admire and respect for his wisdom on issues of nutritional importance spouting something like this, I just gotta scratch my head. How can he come to the conclusion that butter somehow plays a role in raising insulin levels? This just doesn’t seem to make any logical sense with all that we know about the connection between carbohydrate consumption and an increase in insulin. So, like anything else that comes up about livin’ la vida low-carb that has me stumped, I turned to my low-carb expert friends for a response to the notion that butter raises insulin and thus “makes you fat” as Dr. Davis asserts.

Recently I shared a six-minute podcast interview with the great low-carb diabetes legend Dr. Richard Bernstein who wanted to share his thoughts on Dr. Davis’ theory. Here’s a YouTube video presentation of my entire conversation with Dr. Bernstein about this:

What about some other low-carb luminaries? What do they think about this notion regarding butter and the alleged impact on insulin? We’ve already seen some excellent reactions in the blogosphere so far: this incredibly thorough scientific response to Dr. Davis from Peter Dobromylskyj at Hyperlipid , a column called “Saturated fat and insulin function; should low-carbers be concerned?” from S.P.E.E.D. author Jeff Thiboutot, a thought-provoking post entitled “Does Butter Make You Fat?” at the “Nutrition and Physical Regeneration” blog, and “Butter Attacks!” on my buddy Kevin Brown’s “Liberation Wellness” blog. But how about others? Let’s see what they have to say.

DR. ERIC WESTMAN , author of New Atkins For A New You

From the article he cited:

The average total energy provided by the meals was 800 kcal (10 kcal/kg), and the macronutrient profile was as follows: 72% fat, 22% carbohydrate, and 6% protein.

It’s an interesting theory, but I’d like to see this hypothesis studied directly before saying that “butter makes you fat.” For example, a randomized trial or “N-of-1″ study with and without butter.

Colette Heimowitz , spokeswoman for Atkins Nutritionals

The people on the low-carb arm of the study were not low enough in carbs nor were they adapted to a fat-burning metabolism. The study looked at butter intake but the meal also contained pasta so of course insulin will go up. I would highly doubt butter alone or butter with a low-carb food would raise insulin.

NORA GEDGAUDAS , author of Primal Body, Primal Mind

The short chain fats in butter do get absorbed more directly into portal blood, though are burned more preferentially for energy and therefore are not easily stored as body fat (and in reasonable amounts will not provoke an insulin response). Medium and longer chain fats are absorbed into the lymphatic system during digestion and do not have a postprandial blood lipid effect. Also, consider that insulin is NOT a “blood sugar” hormone but does have the job of taking excess nutrients and moving them into storage and/or energy production.

Dietary fat that is truly excessive may potentially provoke insulin to action, although it is much less likely to do so than carbohydrates. Also, fat in the presence of sugar is certainly worse than sugar/starch alone (as fat tends to get put aside into storage while sugar gets preferentially dealt with). Finally, many people are significantly (if not severely) sensitive to casein (the protein milk solids found in milk and, to a lesser degree, butter). Food sensitivity reactions do trigger a cortisol response which, in turn will invariably trigger insulin. Obviously any food to which one is sensitive should clearly be avoided.

DR. WENDY POGOZELSKI , biochemistry professor at SUNY Geneseo

It does seem that if fats are present as well as carbs, the body will use the fats for energy and the rate of the sugar entering cells will be reduced (for a while at least). This is particularly true of the short- and medium-chain fatty acids that are in things like butter and coconut oil. The shorter-chain fatty acids enter the mitochondria without having to go through the carnitine shuttle and they seem to be preferentially used for energy rather than stored. So might be possible that if you eat butter AND you eat carbs, or if you already have hyperglycemia, the pancreas will put out more insulin to compensate for the blood sugar staying high.

Another idea floating around is that fatty acids bind to these receptors called PPARs (peroxisome proliferator-activated receptors). The name is a misnomer. They were discovered in the organelles called peroxisomes but they’re in the outer membranes of many tissues. There are several kinds but the major ones are PPARalpha and PPARgamma. PPARalpha works to increase the amounts of enzymes present that oxidize fatty acids in the liver. It also enhances a fat-burning mechanism called thermogenesis. PPARgamma increases the enzymes that cause enzyme storage in fat cells. (By the way the Type 2 diabetes drugs called the thiazolidinediones, like Avandia, target the PPARs).

One other theory is that saturated fats make membranes more rigid and that the insulin receptors don’t work as well on these more rigid membranes. The counter-argument to this is that people have believed for a long time that the body regulates its membrane fluidity and the body can make unsaturated fatty acids out of saturated ones if need be.

VALERIE BERKOWITZ , author of The Stubborn Fat Fix

The individuals came in to eat test meals for this study but I did not see any info about what type of diet they typically ate which is normally high-carb. This is important because a 12-hour fast will not make someone burn fat vs. carbs. The diet is supposedly low-glycemic but the diet consists of bread, pasta, fat-free yogurt and various fats. Therefore, what this proved is that in the presence of carbs, fat (butter) or more specifically saturated fat will make you fat.

Here’s the problem with the method: The study was done in only 14 healthy males (14 is a very small number). They only test the response to a single meal. It is likely that these 14 men were not in ketosis or they would have reported it even if one meal was low in carb (22% carb, 72% fat) it will not make a difference because they are still burning carbs not fat. It seems the study was actually set up to study how a healthy male responds to eating various fats while burning carbs not fat for energy.

DR. ANDREAS EENFELDT , Swedish doctor and low-carb blogger

Certainly there seems to be some insulin response to dairy, possibly due to the milk protein (and of course the lactose). That said, I hardly think butter is making anybody fat. Milk (and possibly cream and cheese) can be a problem for very sensitive individuals though, as they contains more lactose (milk sugar) and milk protein.

Saying butter can triple insulin levels is only true relative to starvation levels. In the López study, insulin got only marginally higher with butter than with isocaloric meals containing different fats: about 205 pmol/L compared to average about 165 with other fats. Thats about 25% higher, not 200% higher (“tripled”). Additionally there is a lot of statistical uncertainty in those numbers. Plus, butter contains some carbs and protein, the oils do not. So we shouldn’t be surprised that the insulin levels got a bit higher after the butter meal.

If you instead substitute bread for the butter, calorie for calorie, the insulin levels would shoot through the roof. In other words, if eating more butter makes you eat less bread, that will surely make you thinner, not fat. That seems to be the way it works for me and my patients. I eat more butter than ever, more than most people, and I am as thin at 38 as when I was 20.

DR. ROBERT SU , author of Carbohydrates Can Kill

I agree that eating more fats and/or protein, even with carbohydrate-restricted diets, can increase body weight (in either fat tissues and/or muscles). But it is simply a matter of the net sum between the supply and the use of calories. However, many studies on the amount of insulin and its responses to fats were conducted in the study subjects who consumed a noticeable amount of carbohydrates which stimulates the release of insulin and also obscures the response of insulin to dietary fats.

DR. RON ROSEDALE , author of The Rosedale Diet

Saturated fat is harder to burn than more unsaturated fats especially in subjects not conditioned to burn fat as was the case in this study. When you ingest a glycemic load along with the fat as in this study, you cannot burn the fat. And not being able to burn fat underlies all of the chronic diseases of aging.

In this study, the subjects were fed approximately equal portions of high glycemic carbohydrates and fat at the same time. It was not a high-fat diet. It was a high-fat, high carbohydrate diet. These are completely different, one being healthy and one being very unhealthy.

Furthermore, these were fed to subjects not adapted to fat burning. In other words, the only thing that this study showed was my assertion that burning saturated fat is a bit more difficult than burning unsaturated fats, especially in people who have not yet physiologically adapted to burning fat, or I should say have unadapted themselves by long-standing high carbohydrate feeding.

DR. RICHARD FEINMAN , biochemistry professor and Founder of Nutrition & Metabolism

It is the carbohydrate that raises insulin. Butter alone would not raise insulin. (Notice that the controls also raise insulin). The combination of butter and carbohydrate (pasta and bread) appears to have different effect than other fats but the methods says:

“The average total energy provided by the meals was ~800 kcal (~10 kcal/kg), and
the macronutrient profile was as follows: 72% fat, 22% carbohydrate, and 6% protein.”

I get 800 kcal * 1g/4kcal * 0.22 = 44g of carbohydrate in the test meal. Now, I rarely have a meal of 44 g carbohydrate, especially from pasta and bread. It may well be that adding butter to this meal has a greater effect on insulin than olive oil and he wants to say that the effect of insulin on this meal can be generalized to other effects (they don’t really know that the insulin is harmful) but this paper is about high carbohydrate meals, not, as the authors claim, low carbohydrate.

Your well-respected octor believes in carbohydrate restriction? Does he think this paper is about carbohydrate restriction? A good control of pork ribs and brussel sprouts (with butter) and cole-slaw (dinner I just finished) might not have the same effect. Dr. Jeff Volek has clearly shown that post-prandial lipid responses to any fat challenge are improved by chronic carbohydrate-restriction.

DR. MICHAL AZIZ , author of The Perfect 10 Diet

The notion that butter causes weight gain is a sad misconception. The short and medium chain fatty acids in butter are not stored in the adipose tissue, but are used for quick energy. Fat tissue in humans is composed mainly of longer chain fatty acids. These come from olive oil and polyunsaturated oils as well as from refined carbohydrates.

Look at The French? Slim. What do they eat? Saturated fats such as butter. No heart disease, it wans’t called the French paradox for no reason. Look at the Greeks. Overweight. In fact, Greece is number 5 in the world in obesity. What do they eat? Lots of grains and mounounsaturated fats such as olive oil and avoados which are higher in calories. Butter is rich in nutrients, it confers a feeling of satisfaction when consumed. You are less likely to overeat.

The 2008 Lopez study is flawed in many ways. The subjects tested in the study were very small (14 people). A small number of testing individuals cannot give accurate results. Looking at insulin responce alone and once is very misleading in interpreting lasting results. Calories do matter, not insulin repsonse or glycemic index alone. Both a donut and a baked potato have the same glycemic index, but a donut is 4 to 5 times higher in calories and will lead to higher insulin levels and higher levels will persist for a longer time. Was insulin level checked many hours after the meal? No.

Finally, people have different levels of insulin levels and metablism to begin with. Many peope have insulin resistance. You may have the same level of insulin as the person sitting next to you, but your cells do not react to it the same way. How much growth homone did these 14 people have? Growth hormone puts the brake on insulin. It was not checked. In fact, it is never checked in any of thses studies. How long they did these 14 people feel full after that pasta or butter meal? How long were they followed for? The study only looked at one meal.

The findings really look scienific, but it is really nothing more than science fiction to me.

DR. WILLIAM YANCY , Duke University VA Medical Center researcher

I am unaware of fat causing much of an insulin response. General teaching and studies I have seen show that carbohydrate raises insulin a lot (some carbohydrate more than others I imagine), protein some, and fat not so much. I understand there is concern for postprandial lipemia increasing the risk for coronary heart disease. I don’t know that literature well enough to know whether there are threshold effects, or if transient lipemia from a high-fat diet that results in better blood work meal lipemia levels is more or less risky.


You can see that all the mathematical indices of insuling sensitivity and beta-cell function are driven by the difference shown in this table . The fatty acids had no effect on blood glucose, but they increased insulin levels, more so with saturated fats. I can’t find anything definitively showing whether oleate (monounsautrated) or palmitate (saturated) are more easily oxidized to generate ATP than the other. The main regulator of insulin release from the pancreas is the ATP/ADP ratio. So when the pancreatic cell is in a high-energy state, it will release insulin.

It makes sense as a very simple explanation to me that palmitate was most effective at providing easily oxidized energy to the cells. Therefore, pancreatic cells were in a higher-energy state and secreted more insulin. This did not lead to a significant reduction in blood glucose because the fat also provided energy to the muscle cells. Being in a high-energy state, they reduced their cell-surface expression of insulin receptors so as not to overdose on unneeded energy.

However, this study does not clarify the mechanism, so this cannot be said for sure.

The problem with the interpretation fo the study is that it is studying an acute meal effect and trying to draw conclusions about a chronic disease-producing effect. The appropriate study design for this type of interpretation would be to feed high-fat meals of different fatty acid compositions for several weeks or however long it is believed would be needed to have a measurable effect, and then to perform a glucose tolerance test. Instead, they are testing the effect of a single meal of different composition.

This dubiously assumes that the amount of insulin appropriate to a given meal or given carbohydrate load does not depend on the composition of the fats or other components of the meal. What if it is normal and healthy to have a higher insulin response to a meal rich in saturated fats? They are assuming that because diabetes is associated with higher fasting insulin and impaired glucose tolerance that they can use mathematical models designed to test fasting insulin and glucose tolerance to test the acute effect of meals of different composition. This is a logical leap.

It seems to me after hearing from all of these people who know a lot more than I do about this that the concern over butter raising insulin is much ado about nothing. No offense to Dr. Davis or his conclusions, but I’ll happily continue on consuming upwards of 8 tablespoons of my grass-fed, raw butter a day with my low-carb nutritional plan and reap the benefits of high HDL cholesterol, lower triglycerides, greater LDL particle size, and, oh yeah, a reduced weight. That’s what eating healthy butter has done for me over the past six years and I don’t intend to change that anytime soon.

Speaking of, it’s time for another meal. Gotta run and eat me some butter!

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