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  • Haley Schlechter, RD, LDN

Why Keto Did Not Win Top Diet.

Updated: Mar 11, 2020

There have been some pretty angry people all over the internet over the news of the ketogenic diet tying for last on U.S News Best Diets of 2017. Ketogenic dieting is always a hot topic and many people are coming forward to tell their personal testimonies of their great results utilizing the diet. With all these positive testimonials, it’s hard to understand why it would have fallen so low on the list. That being said, there are some inherent reasons why this diet bottomed out. Let’s talk about them.

Some facts first:

The Ketogenic diet first hit the research scene when they found it to be effective for children with severe seizure conditions. Since then, there has been a lot of claims as to its effectiveness in other aspects of health, most notably weight loss.

What is a ketogenic diet though? If I had a nickel for every time the term Keto or ketogenic diet has been used incorrectly, I would be able to buy a whole aisle of pasta. Then I would eat all of that pasta and write this post again. I tend to be a stickler for vocab though, so let’s get our definitions right before we dive in.

A TRUE Ketogenic diet is characterized by eating fat in place of carbohydrates with an unchanged amount of protein. The diet contains 75% of your calories from fat, 20% from protein and 5% from carbohydrates. For reference 5% carbohydrates in a 2000 calorie diet is about 25 grams of carbohydrate or one banana.

A Low Carb diet is generally under 80g carbohydrates and has varying increased amounts of protein and fat. Think Atkins diet.

Carbohydrates are foods and living tissues including sugars, starch, and cellulose. Basically there are carbohydrates in everything except oils, fats and animal meat. So, butter is not a carb, but dairy, fruit and vegetables all are.

Alright, I feel better. So, now that we are all on the same page with definitions, let’s talk results.

And the Research Shows…

If we are talking weight strictly, plenty of studies will tell you that a very low carbohydrate diet will result in weight loss, and some studies found at a much faster rate when compared to a low fat diet as well. Research starts to get conflicting, though, as the length of study increases. What you find in many studies like Foster et al.’s (graph shown), is that many people initially lose more weight in the first 3-6 months on a low carb diet but overtime regain the weight, eventually having similar weigh loss results to conventional diets post 1-year. Here are 2 Systematic reviews (reviews that critically analyze multiple studies) that show no difference in weight loss between low carbohydrate and low fat diets post one year (Naude et al., & Henandez et al. ). What these studies are saying is yes, a low carb diet works but not better than a low fat or simply a low calorie diet long term. This speaks to the well-researched and approved thought that it is more about the caloric balance (calories in v calories out) then that the macronutrient composition of your diet.

The real question is that in a perfect world where all these researched individuals were consuming similar calories just different macronutrients, why does this quick drop and regain occur with low carb groups? Why they drop weight at a faster rate may be due to a few things. The most logical reason to me is simply that carbohydrates require a fair amount of water in order to be processed. The less carbohydrates you consume, the less water the body is retaining, which leads to rapid weight loss initially. Another reason could be that we chronically overeat carbs as a nation. Ask people to reduce this dramatically and they will lose weight. Some other more sciencie hypotheses include:

  • Protein is the most filling macronutrient. Increase protein in low carb diet results in greater feeling of fullness.

  • Breaking down protein for energy requires more calories (energy) then carbohydrate breakdown, resulting in greater calories burned.

  • Original metabolic inefficiency leads to greater metabolic output to convert energy (switching to utilizing fat and protein as main fuel sources).

  • Increased breakdown of fat.

In regards to regain, it is most likely related to the difficulty continuing to follow the diet long term because this isn’t a perfect world where majority of people can sustain the elimination of an entire food group. Many people, myself included, are just never going to eliminate potatoes and pasta long term. It is simply not sustainable for us.

Moral of Story:

It is well discussed that the reason very low carbohydrate diets do not see success long term is related to a difficulty to adhere to the diet long term. Meaning the diet is not sustainable for the individuals involved. So in conclusion: “Ultimately, the best diet is the one the patient will follow and incorporate into his or her daily life for lifelong maintenance of a healthy body weight.” AND that my friends is what I want you to take home from all of this. Different things work for different people. Maybe a lifetime of low carb works for you, maybe it’s low fat, maybe it’s just decreasing portion sizes. Whatever diet or lifestyle you pick, make it one you can sustain long term and that you don’t need a cheat day from.

P.S. If you are an athlete, especially athletes specializing in cardiovascular based sports you really need carbohydrates in order to maximize your performance. Check out my previous research-based post on carbohydrate recommendations for athletes.

Grow Strong My Friends!

Have Questions? Ask!

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