Fact and Fallacy of a Low Carb High Fat (LCHF) Diet

As a Registered Dietitian with a post-graduate degree in Human Nutrition, and a past (published) researcher, it bothers me when people make negative comments about a Low Carb High Fat (LCHF) style of eating, without really understanding what it is – and what it isn’t. This article addresses a few of the common misconceptions that appeared recently in a French-language editorial in the Perspectives section of Le Soleil newspaper (07 septembre 2017, 17h55) and written by several very well-educated and experienced Quebec Dietitians. Certainly, if these esteemed RDs have misconceptions, others do as well. It is my goal in writing this article, to clear up some of these confusions.

FALLACY: “The LCHF diet targets a very low carbohydrate and high-fat diet, aimed at rapid weight loss.”
FACT 1: Firstly, there is no single LCHF diet.

The Atkins Diet is one kind of LCHF diet, so is a Paleo Diet, and these are substantially different from each other. There are LCHF diets written by non-healthcare professionals such as the “Bulletproof Diet”, as well as those from Dr. Jason Fung, a Nephrologist (kidney specialist) from Toronto and from Dr. Eric Westman of Duke University. Referring to “the” LCHF diet fails to take this huge range into account.

FACT 2: There is no one “goal” of LCHF diets.

From my experience, most of the well-designed LCHF diets written by healthcare professionals and researchers are aimed at lowering insulin resistance (IR), which underlies the symptom of high blood sugar and Type 2 Diabetes. Weight loss is a natural byproduct of eating in such a way as to lower IR.

FACT 3: LCHF diets that focus on weight management rarely aim for “rapid weight loss”.

LCHF diets designed by healthcare professionals with a weight management goal generally aim for consistent weight loss and/or inches lost, and reducing abdominal obesity. Morbidly obese people or those with a great deal of weight to lose and who begin eating low-carb will lose weight rapidly at first, firstly from water-loss and then from fat loss. That is not the aim, but the result.

FALLACY: “this diet is so restrictive”…

FACT 4: “this diet…”

Which LCHF diet? As mentioned above, there are many different LCHF-style diets and they differ substantially from each other.

Fact 5: The term “restrictive” is not defined, so this statement really has no meaning.

What are all LCHF diets “restrictive” in?

Foods that are not included on an Atkins Diet are very different from what is not included on a Paleo Diet. Dr. Fung’s recommendations differ from Dr. Westman’s. For example, Dr. Fung does not limit any fats, and Dr. Westman does.

Which LCHF-diet is “restrictive” and in what foods or nutrients?

FALLACY: “this diet is so restrictive that the likelihood that the people who adopt it will drop it in the short or medium term is high.”

FACT 6: The authors didn’t provide evidence that people who adopt a LCHF-style of eating drop it in the short- or medium term because it is restrictive in something.

Which LCHF diet is restrictive and what is it restrictive in? Is there evidence to support that people that stop eating those foods regularly are unable to continue to do so in the short- or medium term?

FALLACY: “There is a difference between processed high-carbohydrate foods such as juice, sweetened beverages, white bread, pastries and sweets, and whole foods high in unprocessed carbohydrates such as brown rice, whole wheat, vegetables, fruits, legumes , which are associated with good health and the prevention of the risk of diabetes, cardiovascular disease and obesity.“.

FACT: 7: all carbohydrates (whether from juice, fruit, pastry, brown rice or whole wheat) are broken down and supply the blood with glucose.

FACT 8: how quickly all carbohydrates are broken down to glucose varies.

FACT 9: how much insulin is released in response to all of these different carbohydrates is what most well-designed LCHF diets endeavor to address.

FALLACY: “Whenever an attempt is made to isolate a nutrient (carbohydrates, proteins or lipids) and make it responsible for all ills, it is wrong. The reality is that we need these three nutrients for the health and enjoyment of eating.”

FACT 10: Well-designed LCHF-diets have all three macronutrients in them; carbohydrates, protein and fat.

The major difference is LCHF diets are low in carbohydrate and high in fat. Which carbohydrates are eaten on different LCHF diets vary. Paleo diets for example eat starchy vegetables that ketogenic-style LCHF diets don’t. In addition, which fats are promoted in the different styles of LCHF diets also differs. Paleo diets are known for promoting lots of red meat, including processed meat such as bacon and sausage and lots of full-fat cream and butter.

LCHF diets, such as the one I teach, include the saturated fat found naturally in foods, such as in steak or in cheese but encourage the “high fat” part of the diet to come from mono-unsaturated fruits such as avocado and olives, from a wide variety of nuts and seeds, as well as from the oils from these foods. It also includes the carbohydrates found in an abundance of non-starchy vegetables, specific fruit, and nuts and seeds. A look at just a few of the recipe ideas posted on this web site, certainly do not indicate a “restrictive diet”.

FACT 11: The Dietary Guidelines in Canada (and the US) have “attempted to isolate a nutrient – fat, and make it responsible for all ills”.

In 1977, the Dietary Guidelines in both countries were first changed to restrict fat intake from all sources, especially saturated fat, in the belief that eating fat contributed to heart disease (see previous articles).

While it is now known that dietary fats do not cause heart disease, and even the Canadian Heart and Stroke Foundation changed their recommendations in this regard, it is my conviction that it was this vilification of fat and the corresponding promotion of diets very high in carbohydrates (45-65% of daily calories as carbs) that contributed to the dual obesity- and Diabetes epidemics that we now have.

Some final thoughts…

It would seem to me that the article published in LeSoleil was an emotionally-charged defense of the Dietetic profession, launched as a reaction to words said during an interview on a Quebec radio program. It did not however come across as a well-thought out analysis by highly educated and experienced Dietitians.

Personally, I don’t feel threatened by the many studies that have been published as far back as 15 or 20 years ago, supporting the use of LCHF-style of eating to address insulin resistance and which as a natural byproduct, promotes weight loss.

While it was both shocking and surprising to me at first, it certainly “fits in” with the pathways I learned in my undergraduate degree – yet promptly set aside to teach the recommendations of Canada’s Food Guide.

A LCHF-style of eating can be done safely, with slow yet consistent weight loss, while monitoring with specific lab work.

It certainly doesn’t have to be restrictive, as one can eat meat, fish, seafood, poultry, cheese and other dairy, vegetables and fruit, nuts and seeds. It can provide a nutritionally adequate diet – certainly no less adequate that the average Canadian eats, following Eating Well with Canada’s Food Guide [see Do Canadian Adults Meet Their Nutrient Requirements Through Food Intake Alone? Health Canada, 2012, Cat. No.: H164-112/3-2012E-PDF].

In conclusion, referring to a wide range of therapeutic diets designed by Physicians and Dietitians as being “absurd” and “dangerous” may paint a bold message with a broad brush that makes for popular journalism, but lacks the evidence-based support that these Dietitians, and our profession is known for.

http://www.lchf-rd.com/

Graham