Tag Archives: Low Carb Diet

Low-Fat Versus Low-Carb Diet: DIETFITS Show Both Can Work If They Are “Healthy”

In the ongoing nutritional war between adherents of low-fat and low-carb diets, the skeptical cardiologist has generally weighed in on the side of lower carbs for weight loss and cardiovascular health.

I’ve questioned the vilification of saturated fat and emphasized the dangers of added sugar. I’ve even dabbled in nutritional ketosis.

The science in  nutrition is gradually advancing and the DIETFITS study recently published in JAMA is a welcome addition.

DIETFITS is a  really well done study which provides important insights into three huge questions about optimal diet:

  1. Should we choose a low-fat or a  low-carb diet for  weight loss and cardiovascular health?
  2. Do baseline insulin dynamics predict who will respond to low-fat versus low-carb diet?
  3. Can we predict who will respond to low-fat versus low-carb by genetic testing?

The Details Of DIETFITS

Stanford investigators recruited 609 San Francisco area individuals between the ages of 18 to 50 years with BMI of 28 to 40  and randomized them to a “healthy” low-fat diet or a “healthy” low-carb diet.

During the first 8 weeks of the study, low-fat participants were instructed to reduce fat consumption to <20 gm/ day while the low carb participants were instructed to reduce digestible carbohydrate to <20 gms/day.

Then individuals were allowed to add back fats or carbs back to their diets in increments of 5 to 15 g/d per week until “they reached the lowest level of intake they believed could be maintained indefinitely.”  Importantly no explicit instructions for energy restriction were given.

The “healthy” instructions for both groups were as follows

  1. maximize vegetable intake
  2. minimize intake of added sugar, refined flours and trans-fats
  3. focus on whole foods that are minimally processed, nutrient dense and prepared at home whenever possible

Dietfits Outcomes-Diet And Weight

Major findings

  1. Total energy intake was reduced by 500-600 kcal/d for both groups
  2. The low-fat vs the low-carb intake at 12 months was 48% versus 30% for carbs, 29 vs 43% for fat and 21 vs 23% for protein.
  3. Mean 12 months weight change was -5.3 kg for low-fat vs 6-6.0 kg for low-carb which was not significantly different
  4. There was no difference between groups in body fat percentage or waist circumference
  5. Both diets improved lipid profiles and lowered blood pressure, insulin and glucose levels
  6. LDL (bad cholesterol) declined more in the low-fat group whereas HDL (good cholesterol) increased more and triglycerides declined more in the low-carb group.

Thus both diets were successful for weight loss and both improved risk markers for cardiovascular disease after a year.

DIETFITS- Can Genes and Insulin resistance Predict Best Diet?

Surprisingly, the study found no significant diet-genotype interaction and no diet-insulin secretion interaction with weight loss.

This means that they could not predict (as many believed based on earlier studies) who will benefit from a low carb diet based on either currently available genetic testing or a generally accepted measure of insulin resistance.

As the authors point out, these findings “highlight the importance of conducting large, appropriately powered trials such as DIETFITS for validating early exploratory analyses.”

DIETFITS-Perspectives

As you can imagine this study has led to quite an uproar and backlash from dedicated combatants in the macronutrient wars.

A reasoned summary and response from Andreas Eenfeldt, a low carb proponent can be found on his excellent low carb/keto Diet Doctor site here.

Eenfeldt concludes

If I’m allowed to speculate, the reason that we did not see any major additional benefit from low carb in this study is that the groups ended up so similar when it came to bad carbs. The low-fat group ended up eating fewer carbs too (!) and significantly less sugar, while the low-carb group ended with a somewhat weak low-carb diet, reporting 130 grams of carbs per day.

Eenfeldt emphasizes that low-fat diets never “win” these macronutrient dietary skirmishes:

On the whole, this study adds to the 57 earlier studies (RCTs) comparing low carb and low fat for weight loss.

From a standing of 29 wins for low carb, zero for low fat and 28 draws, we now have 29 wins for low carb and 29 draws. The wins for low fat stay at zero.

Larry Husten at Cardiobrief.org in his analysis of the study quotes a number of experts including Gary Taubes, the low carb pioneering journalist

Taubes speculates “that the weight loss may have been similar not because any diet works if you stick with it and cut calories (one possible interpretation) but because of what these diets had in common — avoid sugar, refined grains, processed foods. Whether the low-carb arm would have done even better had Gardner kept their carbohydrates low is something this study can’t say. (And Ornish [low-fat diet proponent] would probably say the same thing about fat consumption.)”

The low-fat or vegan disciples seem to have had a muted response to this study. I can’t find anything from John McDougal , Dean Ornish, Caldwell Esselstyn or Joel Fuhrman.

Readers feel free to leave comments which  link to relevant analysis from the low-fat proponents.

Dietfits-Perspective Of The Participants

Julia Volluz at Vox wrote a fascinating piece recently which involved interviewing some of the participants in this study.

She points out that although the average DIETFITS participant lost over 10 pounds, “Some people lost more than 60 pounds, and others gained more than 20 during the year.”

LOW_FAT_LOW_CARBS_DIETS1__1_

She obtained permission from the lead author, Christopher Gardner  and interviewed  “Dawn, Denis, Elizabeth*, and Todd — two low-fat dieters and two low-carb dieters — about their experiences of succeeding or faltering in trying to slim down”

LOW_FAT_LOW_CARBS_DIETS1

I highly recommend reading the entire article for details but Volluz concludes

And that leads us to one of the burning mysteries of diets: how to explain why some people fail where others succeed — or the extreme variation in responses. Right now, science doesn’t have compelling answers, but the unifying theme from the four study participants should be instructive: The particulars of their diets — how many carbs or how much fat they were eating — were almost afterthoughts. Instead, it was their jobs, life circumstances, and where they lived that nudged them toward better health or crashing.

DIETFITS-Importance of “Healthy” Diet

Most likely the success of both of these diets is due to the instruction that both groups received on following a “healthy” diet. This guidance is remarkably similar to what I advocate and is something that combatants in the diet wars ranging from paleo to vegan can agree on.

The JAMA paper only provides the description I listed above but Volluz adds that participants were instructed to:

… focus on whole, real foods that were mostly prepared at home when possible, and specifically included as many vegetables as possible, every day … choose lean grass-fed and pasture-raised animal foods as well as sustainable fish ... eliminate, as much as possible, processed food products, including those with added sugars, refined white flour products, or trans-fats … prepare as much of their own food as possible. …

Indeed, if you want to see a very detailed description of the instructional process for participants check out the very detailed description of the methods here.

Yours in Health,

-ACP

N.B. I was searching for a reasoned response to this study from the low fat camp and to my surprise came across this fascinating video featuring the lead author of the study, Christopher Gardner, on (no fat/vegan) John McDougal’s YouTube site. Gardner is clearly on the side of sustainable, local , ethical food consumption but to his credit, his research , publications and comments on DIETFITS don’t reveal this.

A Farewell to Ketosis: Banting, Dickens and The Roots of Atkins

The skeptical cardiologist spent an interesting week in ketoland, counting carbs, and turning ketostix purple,  but ultimately decided this was not a world he wanted to inhabit long term.

letter-on-corpulence-by-william-banting3During that week I paid 1.99$ to download William Banting’s “Letter on Corpulence”(available here for free.) Banting, writing in 1869, first popularized a low carb, high fat diet for obesity with this pamphlet. He starts it off with these words:

“OF all the parasites that affect humanity I do not know of, nor can I imagine, any more distressing than that of Obesity, and, having emerged from a very long probation in this affliction, I am desirous of circulating my humble knowledge and experience for the benefit of other sufferers, with an earnest hope that it may lead to the same comfort and happiness I now feel under the extraordinary change,—which might almost be termed miraculous had it not been accomplished by the most simple common-sense means.”

The pamphlet was enormously popular and sold over 60,000 copies. Banting donated his 225 £ of profit to various charities, including:

charles_dickens__2_
Charles Dickens, twice President of the Printer’s Pension Society and also did some writing. In the Pickwick Papers, he describes Joe, the Fat boy, who was perpetually falling asleep. Pickwickian Syndrome was the early medical term for what is now sleep apnea.

FatboyJoe“£ s.d.

To The Printers’ Pension Society, at the

Anniversary Dinner, in March, 1864,

per Chas. Dickens, Esq. .. .. 50 0 0″

 

 

In my last post, I closed with a paragraph  describing the benefits I had experienced of consuming a really high fat, very low carb diet: more energy, less sleep needed, asthma cured, wrinkled skin “melting away. This was supposed to be a humorous parody of how enthusiastic supporters of fad diets feel after they have jettisoned their bad eating habits but apparently most readers, unaware of my dry sense of humor (or perhaps not familiar with David Cronenberg’s The Fly) took this seriously.

Certainly, if I had felt significantly better on the Atkins diet I, like William Banting,  would still be on it. Alas, if anything, I felt worse.

My sleep was unaffected. Unllike, Robert Atkins, who noted his sleep requirements went from 8 hours a night to 5 hours a night, my sleep patterns were unchanged.

Energy levels in the morning were good but periodically in the afternoon, especially after even minor exertion but particularly after an intense workout, I would feel uncharacteristically exhausted.

Although my weight dropped 3-4 pounds this is typically what happens if I cut out alcohol from my diet for a week so it’s hard to say what the independent role of the extremely low carb intake and ketosis was.

My blood pressure dropped during the week and I had to cut back on my blood pressure medications to avoid dizziness. There were too many other variables occurring simultaneously that week (weight loss, lack of alcohol consumption) to know if this was independently associated with the ketogenic diet, however.

To be fair, supporters of ketogenic/Atkins diets warn us that during  the initial weeks, we may feel worse, experiencing the so-called “low carb flu.” To fully test it I should have stayed on it for 3-6 weeks and entered a maintenance phase in which I could have consumed more carbohydrates.

However, after a week of having to analyze in detail the carb or net carb content of everything that I consumed, I realized this was not something I wanted to do long term.

For the significantly obese like William Banting who  struggle to achieve weight loss the ketogenic/Atkins diet is likely to be a much better experience than for someone like me who is not overweight. Banting’s diet prior  to his “miraculous change” consisted primarily of bread, milk and beer and it is likely that cutting out the bread and beer alone would have had a dramatic effect on his weight and well-being.

My adventure in ketoland inspired me to update my dietary recommendations , the pdf of which is here (What Diet Is Best For Heart Health).

It would nice if we had some sort of genetic test that would tell us what diet is perfect for us. Unfortunately, until that is developed, trial and error is the only viable approach. Some, like William Banting, Robert Atkins and the  lady at zerocarbizen.org will thrive on very low carbs whereas others, like Dean Ornish and Nathan Pritikin prosper on a very low fat diet.

Most individuals will be served best by a diet of real, minimally processed food with lots of different vegetables growing both above and below ground and eaten in moderation.

Unbantingly Yours

-ACP

N.B. Here, in a nutshell, in Banting’s own words ,is the essence of the Banting diet:

“I never eat bread unless it is stale, cut thin, and well. toasted. I very seldom take any butter, certainly not a pound in a year. I seldom take milk (though that called so, in London, is probably misnamed), and I am quite sure that I do not drink a gallon of it in the whole year. I occasionally eat a potato with my dinner, possibly to the extent of 1 lb. per week. I spoke of sherry as very admissible, and I am glad of this opportunity to say, that I have since discovered it promoted acidity. Perhaps the best sherry I could procure was not the very best, but I found weak light claret, or brandy, gin, and whisky, with water, suited me better; and I have been led to believe that fruit, however ripe, does not suit me so well taken raw as when cooked, without sugar. I find that vegetables of all kinds, grown above ground, ripened to maturity and well boiled, are admirable; but I avoid all roots, as carrot, turnip, parsnip, and beet. ”

Excerpt From: William Banting. “Letter On Corpulence.” Foster, 2014. iBooks. https://itun.es/us/fOKP3.l

Adventures in Ketoland or How I learned To Love The Purple Stick

In the name of research and inspired by reading a biography of Robert Atkins, a few days ago the skeptical cardiologist embarked on an ultra low carb diet designed to put him in a state of ketosis.

IMG_6621Robert Atkins, the “cardiologist” who popularized the ultra low carbohydrate, high fat diet (LCHF) with his 1972 book “Dr. Atkins Diet Revolution,” admonished his patients: “Now remember, happiness is a purple stick!”

When the body shifts to utilizing fat for energy rather than glucose, the result is the production of ketone bodies which can be detected in the urine by use of a ketostick. When your urine turns the stick purple, you have become ketotic and have successfully kept your carbohydrate intake low.

Entering ketoland, as I like to term it, is not for the faint of heart. It requires a fanatical devotion to the LCHF pope, a steely determination, and meticulous monitoring of your food for anything that resembles a dreaded carb.

Nutritional Ketosis versus Diabetic Ketoacidosis

My first experience of ketosis was as a third year medical student on the vast, communal wards of St. Louis City Hospital. Here, the teeming indigents, the IV drug abusers and the criminals of the city came to share graciously their noxious diseases with we innocent disciples of Hippocrates.

Amongst the patients with AIDS and endocarditis, pheochromocytoma and Mallory-Weiss syndrome, there were many insulin-dependent diabetics who, for themselves, poorly did care or who had decompensated due to infection.

Emanating from their mouths and other orifices, I, not uncommonly,   noted a peculiar odor. It smelled like pear drops or ripe apple or perhaps, (had I been familiar with it at the time) nail polish remover, and was quite distinctive. Most of my fellow students could not smell it and relied on blood or urine tests to confirm what I had already detected-KETONES!

These diabetics had gone into diabetic ketoacidosis (DKA), a life-threatening complication and I was smelling acetoacetic acid.

Peter Attia has written eloquently and interestingly about the difference between DKA and nutritional ketosis here. You can only get the dangerous type of DKA if you are unable to produce insulin like type I diabetics.

Attia tells this embarrassing story:

“I remember exactly where I was sitting in a clinic at Johns Hopkins in 2002 explaining to (admonishing, really) a patient who was on the Atkins diet how harmful it was because of DKA.  I am so embarrassed by my complete stupidity and utter failure to pick up a single scientific article to fact check this dogma I was spewing to this poor patient. If you’re reading this, sir, please forgive me. You deserved a smarter doctor.

I’m pretty sure that,to this day, there are many doctors who only think of DKA when they hear the term ketosis.

Ketoland Deconstructed

The ketoland I have entered is not pathological: Atkins and, increasingly in the last decade, evidence-based and academic nutrition scientists, believe that ketosis may be a healthier state for our body to be in, free of wildly fluctuating,  inflammatory insulin cycles.

The cost of admission, however, is eschewing all bread, pasta, rice, potatoes, sugar-sweetened beverages, pastries, processed foods and, obviously, candy…that’s right out.

The tantalizing part of the diet is that it does not restrict your intake of fat in any way. In fact, to have your ticket punched into ketoland you must seek out fat in as pure a form as possible.

This morning, for example, I made myself a cup of coffee and adulterated it with heavy whipping cream (0 carbs, 50 calories of fat). Before leaving the house I took two boiled eggs and mixed them with mustard and safflower oil mayonnaise (30 grams of fat, no carbs) to eat later in the day.

I eat burgers, no fries, no buns, and I carry with me macadamia nuts, sunflower seeds, and almonds. I bought a huge jar of coconut oil and eat it by the teaspoon.

IMG_6615
An Atkins-aware dinner for me meant including my laptop with software to calculate the amount of carbohydrates per serving and measuring cups to precisely measure out the sour cream, guacamole and tex-mex low carb casserole portions. Kudos to the eternal fiancee’ for seemingly tolerating all this.

Ketoland is foreign territory for most of us. I had to enter foods into the myfitnesspal app to help me determine what the carbohydrate contents were.  I found myself paying close attention to portion size, not for the calories, but to help me better estimate how many carbs I was consuming.

For example, I thought that cauliflower would be a good snack, but 4 pieces of cauliflower cost me almost 5 carbs.

Happiness Is A Purple Stick

IMG_6616After 12 hours, during which I consumed 123 grams of fat, and only 26 grams of carbohydrates, my ketostick turned purplish.

What is it like in ketoland? Well, for one thing I only need 4 hours of sleep.  Asthma, which has plagued me all my life, is now nonexistent. Wrinkles have melted from my face, like wax from a burning candle. I have boundless energy. The best comparison I can come up with is the transformation Jeff Goldblum underwent in David Cronenberg’s (1986) The Fly. Come to think of it, he was probably also on a LCHF diet. Hopefully, I won’t experience his complete transformation.

****Warning. The above paragraph is an attempt at humor. None of it is true. Warning******

Seriously, I think it is too early to tell whether the tediousness of this diet will be worth it for me, but if I can last for a few weeks, I will have some good anecdotal short-term data to share with my patients on the diet’s effects on weight, energy, hunger, and personality.

Admonishingly Yours,

-ACP

If you are wondering why we make ketones, here’s a simple answer from Peter Attia.

For starters, it’s a vital evolutionary advantage.  Our brain can only function with glucose and ketones.  Since we can’t store more than about 24 hours worth of glucose, we would all die of hypoglycemia if ever forced to fast for more than 24 hours.  Fortunately, our liver can take fat and select amino acids (the building blocks of proteins) and turn them into ketones, first and foremost to feed our brains.  Hence, our body’s ability to produce ketones is required for basic survival .

If you’d like to watch a very well done 11 minute video on low carb high fat diets click here. You have to give an email address, which will send you Andreas Eenfeldt’s Diet Doctor updates. His site is very well done, free of ads and free of any industry influence.

You should be able to watch his diet revolution video, full of Swedish humor here.

Scintillating Findings From New Orleans: Low Carb Diet Is Better than Low Fat for Losing Weight and Preventing Heart Disease

The SC and the Significant Other of the SC at Commander's Palace following an investigation of shrimp and grits.
The SC and the Significant Other of the SC at Commander’s Palace following an investigation of shrimp and grits.

The Skeptical Cardiologist is in New Orleans this weekend on a dedicated quest to research low carb diets.

The low fat diets recommended by government guidelines and national organizations like the American Heart Association don’t help most individuals lose weight and they don’t lower  the risk of heart disease. It’s very hard to understand why these are still promulgated by these organizations.

Some diets, such as the Atkins, South Beach and Paleo diets, advocate very low carbohydrate consumption and have helped many successfully lose weight.  However, due to the high fat in such diets, there has been concern about their overall effect on  cholesterol levels and heart disease.

A new study published in the Annals of Internal Medicine addressed the question of which of these dietary  approaches is best. Researchers at Tulane University (located inNew Orleans!)  randomly divided   148 obese (BMI>30) men and women (88% were women and 51% were black) into two  groups: a low-carbohydrate group that was encouraged to consume no more than 40 grams of carbohydrates  per day (the amount of two slices of  bread), and a low-fat group, which was encouraged to consume less than 30 percent of their calories from fat and 55 percent from carbohydrates (based on the National Education Cholesterol Program guidelines).

Interestingly neither group was instructed to lower their overall calorie consumption and both groups were instructed NOT to change their overall physical activity level (the researchers were trying to minimize factors effecting their results other than the percentage of fat/carbs).

The funding source for the study was the National Institutes of Health so we can consider the study unbiased by industry.

After 12 months, the low-fat group had lost 1.8 kg (2.2lbs=1kg) and the low-carb group had lost 5.3 kg.

The low-carb group had lost 8 pounds more, a difference that was highly  statistically significant (p<.001).

In addition, in the low-carb group fat mass had declined by 1.2% whereas it had risen by 0.3% in the low-fat group.

In other words, the low-carb group was losing body fat but the low-fat group was just losing lean body mass.

My patients, like most Americans, have had the lie that fat consumption causes obesity and contributes to fatty plaques in their arteries drummed into their heads for decades and fear low-carb diets because of concerns that they will cause their cholesterol levels to rise and increase their risk of heart disease.

This new study, however, showed that the low-carb diet (with almost double the amount of saturated fat consumed compared to low-fat diet) actually improved the subjects’ heart risk profile.

Low Carb Diet Improves Cardiac Risk Profile

At 12 months, there was no difference in the total or LDL (bad cholesterol) levels between the two groups. However, the good (HDL) cholesterol had significantly increased in the low-carb group causing a decrease in the ration of total to HDL cholesterol. The low-fat group had no increase in HDL. Triglycerides dropped in both groups but significantly more in the low-carb group.

Atherosclerosis is not just related to the cholesterol profile as I have discussed here,  but it is a complex process involving multiple factors, including inflammation.  A simple blood test, the C-reactive protein or CRP tracks inflammation. The CRP dropped by 6.7 nmol/L in the low-carb group and rose by 8.6 nm/L in the low-fat group. Lower CRP levels have been associated with lower risk of cardiovascular events in multiple studies.

This was a small study (but actually one of the largest prospective dietary studies available) but really well done.

The major take home points are as follows:

  1. Low-carb diets for many are a very effective weight loss approach
  2. Low-carb diets, even with their higher saturated and overall  do not adversely effect the cholesterol profile or increase risk of heart disease.
  3. This study suggests that low-carb diets improve good cholesterol, lower inflammation and are likely, therefore, long term to reduce the risk of heart attacks and strokes.

Realistic Dietary Approaches

I have found the extremely low-carb diets such as Atkins to be very hard for my patients to follow long term.  Some modification of  the strict limits on carb consumption are necessary I think to make diets interesting and healthy.

Although the goal of this study was to have the low-carb group consume less than 40 grams, the average carb consumption was 93 grams at 6 months and 127 grams at 12 months, a much more sustainable level of carb intake.

The first and most important thing anyone can do if they  want to lose weight and improve their cardiovascular risk profile is eliminate added sugar from their diet.

Sugar-sweetened beverages are an easy first step. But equally important is avoiding foods masquerading as healthy due to their low fat content. Low-fat yogurt and smoothies, for example, are loaded with empty sugar calories. You are much better off consuming the full fat varieties as I have pointed out here.

This is the Skeptical Cardiologist signing off from beautiful New Orleans where my next investigation will be on the cardiovascular consequences of crawfish étouffée plus dixieland jazz.