Category Archives: Low-Carb

Study Finds: “Short-Term Benefits Of Low-Carbohydrate Diets For Weight Loss Are Potentially Irrelevant”

BCA1D9Before I leave this topic, for now at least, here’s one more study* that found eating a low-carb diet leads to earlier death:

Low-Carbohydrate Diets And All-Cause Mortality: A Systematic Review And Meta-Analysis Of Observational Studies, PLoS One, January 2013

Low-carbohydrate diets were associated with a significantly higher risk of all-cause mortality.

These findings support the hypothesis that the short-term benefits of low-carbohydrate diets for weight loss are potentially irrelevant.

Given the facts that low-carbohydrate diets are likely unsafe and that calorie restriction has been demonstrated to be effective in weight loss regardless of nutritional composition, [36] it would be prudent not to recommend low-carbohydrate diets for the time being. Further detailed studies to evaluate the effect of protein source are urgently needed.

Interestingly, this was a similar mortality risk to the onestudy in my last post, 31% increased risk here, 33% in Harvard’s analysis of the large Nurses’ Health Study and Health Professional Follow‐Up Study cohorts:

The risk of all-cause mortality among those with high low-carbohydrate score was significantly elevated: the pooled RR (95% CI) was 1.31 (1.07–1.59).

There’s something about eating a lot of animal food that just isn’t good. I’ve said for years now that how we raise animals for food is contributing to chronic disease in humans. It’s more than saturated fat and cholesterol, although they play a part. Animals are higher up on our food chain. Being so, they bioaccumulate POPs (Persistent Organic Pollutants) which have been linked to a range of metabolic disorders. Since POPs are often hydrophobic or lipid soluble, there are higher levels in an animal’s body fat, including our own.

If you’re eating a high-fat diet and that fat is coming from cheese, eggs, bacon, butter, and other animal sources, you’re being exposed to more environmental pollutants than if you are eating either a low-fat diet or a plant-based diet.

* Thanks to @albie_cilliers who posted this in his Twitter stream.

Another Study Defined A Low-Fat Diet As 30% (Of Calories)

LowCarbVsLowFat2A study was recently published that concluded low-carb diets were better than “low-fat” diets for weight loss and cardiovascular disease markers:

Effects of Low-Carbohydrate and Low-Fat Diets: A Randomized Trial, Annals of Internal Medicine, 2 September 2014

The first thing I looked at was the low-fat group’s fat intake. Their goal was anything less than 30%. They ended up eating 29.8%. This is not low-fat, neither their goal nor their actual intake. A true low fat diet is something less than 15%. I often say

… that in studies comparing one group to another, you won’t detect a harmful effect of _____ if both groups are exposed to a level of ______ that is risk-producing. … If you want to know if something is harmful – smoking cigarettes, eating saturated fat, watching television – make sure you have a comparison group that isn’t doing it, or isn’t doing very much of it.

I also noticed that the low-carb group was eating fewer calories. Since it’s possible to lose more weight when you’re eating less, I was surprised this piece of data was not made more prominent.

Dr. Campbell parsed the study too: Low Carb Hot Air – Again, Again and Again!

Campbell said:

The researchers’ definition of a low fat diet is blatantly false. They assume that a 30% fat diet is low fat, which is not very different from the standard American diet (SAD) at about 35-37% fat. A Whole Food, Plant-Based (WFPB) diet, a truly low fat diet is around 8-12% fat.

In summary, two dietary characteristics illustrate the problem with this latest study, 1) the low fat diet is not low fat and 2) the consumption of truly healthful whole plant-based foods is very low in both diet groups, with no discernible difference between the diets. Together, these two characteristics negate any possibility of observing meaningful results. Both experimental diets are pro-inflammatory, high in fat and very low in foods that actually create health. In no way does it speak to the health benefits demonstrated by the truly low fat WFPB diet.

Gary Taubes’ Typical Low-Carb Diet, And Lab Results

SteakEggs3Gary Taubes, author of “Good Calories, Bad Calories,” and “What If It’s All Been A Big Fat Lie?” is an advocate of low-carbohydrate diets. He posted the results of his blood test on his site about 3 years ago, along with this description of his usual diet:

“Keep in mind as you go through these that I do indeed eat three eggs with cheese, bacon and sausage for breakfast every morning, typically a couple of cheeseburgers (no bun) or a roast chicken for lunch, and more often than not, a ribeye or New York steak (grass fed) for dinner, usually in the neighborhood of a pound of meat. I cook with butter and, occasionally, olive oil (the sausages). My snacks run to cheese and almonds. So lots of fat and saturated fat and very little carbohydrates. A deadly diet, according to Dr. Oz.”

I don’t want to post his lab results here; I feel that’s invasive, even though he made them public. The only values that fell out of the lab’s “reference range” were his total cholesterol (204 mg/dl) and carbon dioxide (19 mmol/L, should be below 21). His LDL was 116.

This is the diet he purports will turn around the epidemics of obesity and diabetes. It is the diet he recommends for avoiding heart disease and cancer. Keep in mind that over 100 million people in this country have diabetes or prediabetes, more than a third of the entire US population. Can you imagine how things would change if suddenly millions of people started eating mostly animal food? No grains, no beans, no potatoes, no fruit?

Taubes’ foundation NUSI has already raised $40 million and is on track to raise $190 million. There’s a lot of funding behind this diet. I think that’s one reason we’re seeing it advanced more in the media.

Some Thoughts On Dr. Perlmutter’s “Grain Brain”

GrainBrainCover2I finally went to yesterday and skimmed through the book Grain Brain. The author, Dr. Perlmutter, is an award-winning, practicing neurologist. The book was a number one New York Times bestseller. Perhaps he has something to say.

Grain Brain: The Surprising Truth About Wheat, Carbs, and Sugar – Your Brain’s Silent Killers, by David Perlmutter and Kristin Loberg, September 2013

With “grain” in the title, I assumed the book was about avoiding gluten, a protein found in some grains. Was Perlmutter going to argue that gluten impacts neurological function? The full title, which I just saw now, is telling me it isn’t about gluten, not exclusively. It’s about carbohydrate.  So, is he arguing that dietary carbohydrate impacts neurological function? Any food with carbohydrate in it? Quinoa? Rice? Beans? Apples? Carrots? Lemons? Potatoes? Just about all plant foods contain carbohydrate.

Here’s what I found from Amazon’s “Look Inside”

Modern grains are silently destroying your brain. … I’m referring to all the grains that so many of us have embraced as being healthful – whole wheat, whole grain, multigrain, seven-grain, live grain, stone-ground, and so on.

I will demonstrate how fruit and other carbohydrates could be health hazards.

… An extremely low-carbohydrate but high-fat diet is ideal (we’re talking no more than 60 grams of carbs a day – the amount in a serving of fruit). This may also sound preposterous, but I’ll be recommending that you start swapping out your daily bread with butter and eggs. You’ll soon be consuming more saturated fat and cholesterol and re-thinking the aisles in your grocery store.

In the days leading up to your new way of eating, you’ll want to take an inventory of your kitchen and eliminate items that you’ll no longer be consuming. Start by removing the following … All forms of processed carbs, sugar and starch: corn, yams, potatoes, sweet potatoes.

The following can be used in moderation (“moderation” means eating small amounts of these ingredients once a day or, ideally, just a couple times weekly):
– Carrots and parsnips.
– Legumes (beans, lentils, peas).
– Non-gluten grains. (Avoid oats entirely.)
– Whole sweet fruit: Berries are best; be extra cautious of sugary fruits such as apricots, mangoes, melons, papaya, prunes, and pineapple.

I’m going to rescue you from a lifetime of trying to avoid eating fat and cholesterol and prove how these delicious ingredients preserve the highest functioning of your brain. … Our bodies thrive when given “good fats,” and cholesterol is one of these. And we don’t do so well with copious amounts of carbohydrates, even if those carbs are gluten-free, whole grain, and high in fiber.

Eating high-cholesterol foods has no impact on our actual cholesterol levels, and the alleged correlation between higher cholesterol and higher cardiac risk is absolute fallacy.1

You will be starting a daily supplement regimen for life. [Perlmutter sells supplements on his site.]

Yes, Perlmutter is saying that any intake of carbohydrate, beyond the 60 or so grams in a piece of fruit, impairs brain function. It’s evident that Dr. Perlmutter’s food journey and mine have led to drastically different diets. (At least he allows small amounts of beans. On a Paleo diet, you have to avoid them at all costs, even fresh green beans.)

Here’s a comment by srj, who claimed to be a physician. It’s representative of other comments which call into question Perlmutter’s treatment of the evidence:

“I quit reading about half way through the book because in almost every case he badly misinterpreted the studies he quoted. As an example, reference 25 in Chapter 4 (Title: Effects of Dietary Composition on Energy Expenditure During Weight-Loss Maintenance) compared people on a high glycemic diet, a low glycemic diet (whole grain) and a very low carbohydrate (high fat/meat) diet. This study did show a slight improvement in metabolic syndrome components in the low carb diet over the low glycemic diet, but the low carb diet raised cortisol and CRP (C-Reactive Protein) levels considerable. Previous studies have shown a 5-fold (that’s 500%!) increase in cardiovascular mortality with the higher levels of cortisol and CRP and thus the conclusion of the study authors was that the low carb diet was too dangerous to recommend. The only part of the study reported by Dr. Perlmutter was that that the metabolic syndrome parameters were better – nothing about the cortisol and CRP elevation which was far more important.”

I’m surprised at the assurance with which Perlmutter advances his ideas. Dr. David Katz, founding director of Yale University’s Prevention Research Center, criticized Grain Brain, saying many of its claims were “wildly preposterous,” particularly the one where Perlmutter says the ideal diet “is close to that of the Paleo diet: 75% fat, 20% protein, and 5% carbs.” Katz, citing work of researcher and “The Paleo Diet” author Lorin Cordain, said that humans during the Paleolithic Era ate mostly plants with a scattering of seeds and nuts. … “What the hell could they possibly have eaten that would be that fatty?”2

Maybe we’re all a little guilty of focusing on science that supports our preconceptions and glossing over that which challenges them. It’s our prerogative. Most of us aren’t writing books, selling products, and collecting consulting fees. Don’t you think that someone who is presenting himself as an authority, who claims to be science-based, who is urging millions of people to adopt a controversial diet, would be more even-handed with the evidence? I do. The reason I support eating a whole-food, plant-based diet is because I’ve read the studies, not because I’ve read a book by someone claiming to have read the studies for me.

1 This particular claim has been exhaustively researched by a blogger who goes by Plant Positive. He refers to people who reject the lipid hypothesis, as Perlmutter does here, as cholesterol deniers. He’s amassed a trove of evidence that defends the lipid hypothesis, that defends the correlation between serum cholesterol and heart disease, i.e. the lower your cholesterol, the lower your heart disease risk.
2 James Hamblin’s skepticism is wholly transparent in his Atlantic article, “This Is Your Brain On Gluten.“)

Low-Carb, High-Fat Diets Linked To Poor Artery Function


Angina pectoris is chest pain due to poor functioning of arteries supplying the heart.

The New York Times’ Mark Bittman and Time Magazine’s Bryan Walsh may be telling us to eat butter, suggesting that dietary fat is not a problem, carbohydrates are the problem. But researchers in Spain said there is a …

Negative effect of a low-carbohydrate, high-protein, high-fat diet on small peripheral artery reactivity in patients with increased cardiovascular risk, British Journal of Nutrition, April 2013 (pdf)

This was a cross-sectional analysis of 247 men and women.  Patients eating the least fat and the most carbohydrate (45% carb, 20% protein, 32% fat) had better small artery function than those eating the most fat and least carbohydrate (29% carb, 24% protein, 40% fat).

“Conclusion: In a cross-sectional study of patients with increased CV [cardiovascular disease] risk, a dietary pattern characterised by a high LCDS (high protein and fat, but low carbohydrate content) was associated with poorer peripheral small artery function compared with individuals consuming a diet with a lower LCDS. The association was strong in patients with two different metabolic diseases studied: the MS [Metabolic Syndrome] and T2D [Type 2 Diabetes].”

“Fat Affects Your Blood Sugars”

I was reading a post, “Gary Taubes and the Cause of Obesity” on a site called ScienceBasedMedicine. The author, Harriet Hall, said:

“… serum insulin levels are driven by the carbohydrate content of the diet.”

Many people think this. As you know, it is inaccurate. Dietary carbohydrate is not the sole driver of serum insulin. But it persists in people’s minds. It is the reason people go on low-carb diets … thinking they can reduce their blood glucose and insulin by eating fewer carbs. Unfortunately, that means eating more fat and…

High-fat diets have been shown to increase insulin levels, because fat (especially saturated fat) can decrease insulin sensitivity. When cells become resistant to insulin, the pancreas produces more insulin to compensate, resulting in high serum insulin levels or hyperinsulinemia.

Also, when cells becomes resistant to insulin, glucose in the blood can’t enter cells so blood glucose levels rise.

Here’s an unfortunate result … high insulin levels can feed insulin resistance, which can feed high insulin, which can feed insulin resistance … in a self-propagating manner:

Insulin Resistance and Hyperinsulinemia, Is hyperinsulinemia the cart or the horse? Diabetes Care, 2008

That quote in my title, “Fat Affects Your Blood Sugars” came from this video out of the Joslin Diabetes Center. People think it’s just the carbs that affect blood sugar; it’s the fat too:

Taubes: 10,000 Calories Can Leave You Hungry (If It’s Mostly Carbs). Really?

In the video below, Gary Taubes tells the story of prisoners who were given additional carbs on top of their baseline diet (of about 3000 calories). They ate a lot, “as many as 10,000 calories a day.” “And then they said they’d go to bed hungry.” But when fat was added to their diet instead of carbs … no, they couldn’t add fat to their diet, the prisoners’ eating urge prevented it. (He doesn’t say, but I assume the “baseline” diet was composed of a mix of carbs, protein, and fat in something like the typical American diet: 55/15%/30%, not itself a “low-carb” or high-carb” diet.)

I like this point he raises about appetite. Appetite is a crucial component of our body’s weight management system.

“You can’t divorce the regulation of appetite from the regulation of energy storage. … If you try to force someone to overeat it’s going to feed back on appetite and energy expenditure, in such a way that they’re not going to be able to do it.”

In his example above, Taubes said that carbohydrate doesn’t feed back on appetite, but fat does … that when the prisoners ate fat, their appetite waned, but when they ate carbohydrates, their appetite was sustained. But 10,000 calories and still hungry? I’m having a hard time with that…


Photo of the actual food participants ate during The Evo Diet Experiment. From BBC.

Remember the Evo Diet? A group of volunteers were housed at a British zoo for 12 days and fed “the sort of diet our ape-like ancestors once ate.” Each morning a cooler containing 11 pounds of fruits, vegetables, and nuts was delivered to each participant (see photo). It was a very high-carb, low-fat diet that provided enough calories so that participants wouldn’t lose weight. Well, participants lost weight. Many couldn’t finish their 11 pounds of food.

After just 12 days on the Evo Diet:

  • Cholesterol dropped 23% (e.g. From 210 to 162 mg/dl)
  • Blood pressure dropped from 140/83 to 122/76
  • Weight dropped 9.7 lbs

Barnard et al. found the same thing when he told his study participants, who were not in a zoo but were free-living, and who had diabetes no less, to eat unlimited amounts of whole plant food (cooked or raw).1  That included … potatoes, squashes, corn, rice, oats, wheat, beans, legumes, and all manner of fruits and vegetables.  It was very high-carb, over 70% of their food energy came from carbohydrates.

After 6 months on the whole food plant-based diet:

  • Weight dropped 14.3 pounds
  • HbA1c fell 1.23 points (HbA1c is a measure of blood glucose)
  • LDL cholesterol fell 21.2%

They also experienced reductions in BMI, waist circumference, total cholesterol, had improved kidney function, and many reduced their diabetes medications. They were eating unlimited amounts of food.

It is simply not true that a diet of mostly carbohydrates is not satisfying or cannot contribute to weight loss.

1A Low-Fat Vegan Diet Improves Glycemic Control And Cardiovascular Risk Factors In A Randomized Clinical Trial In Individuals With Type 2 Diabetes, Diabetes Care, August 2006

Dr. McDougall On “Wheat Belly” And “Grain Brain”

Several people have asked me what I think of two books … Wheat Belly by Dr. William Davis and Grain Brain by Dr. David Perlmutter. I haven’t read either of them yet. It looks like Dr. McDougall has. He says they constitute low-carb, “backdoor” Atkins’ diets which are, in the long term, bad for your health.

Here’s Dr. McDougall presenting at his Advanced Study Weekend a few weeks ago. He addressed these two books and the low-carb diet overall. He doesn’t hold back!