Bacon and Sausage and Cheese…Oh My!

If I told you that you could eat all of the bacon, heavy cream and butter you desire at the expense of your daily oatmeal and pasta, would you do it?

By following a ketogenic diet, that’s exactly what you will be doing.

“Keto” has become quite the buzz word lately in the diet world. All of a sudden, carbs have become the devil, people are drinking coconut oil in their coffee and incorporating all kinds of fats into their diet in hopes of losing the dreaded ‘winter weight’. How did this all start? Is research proving some truth to the low-carbohydrate, high-fat phase that so many Americans lately have found themselves in?

It’s Not Exactly Something New

There was a point in time when the ketogenic diet wasn’t called ketogenic. The low-carb movement started as the Atkins diet, which has been used for several decades to help people lose weight. Created by an American cardiologist named Dr. Robert Atkins, this diet was thought to help shed extra fat, but there is weak evidence supporting its effectiveness long-term (Dr. Axe).

Besides weight loss, for over 100 years this low-carb diet regimen has been prescribed for other therapeutic uses. It has been used to help combat drug-resistant epilepsy, especially in children (Harvard Health Publishing). There are also claims that following a ketogenic diet can help with Parkinson’s, Alzheimer’s, multiple sclerosis, sleep disorders and even autism, but there has yet to be credible human studies that support this (Harvard Health Publishing).

What Effect Does This Diet Have on Our Bodies?

Essentially, the ketogenic diet causes the body to release ketones into the bloodstream. Ketones are produced to give our bodies energy in times of fasting or starvation. Most of the cells in our bodies prefer to use carbohydrates for energy. When we aren’t eating these carbohydrates, we will start to break down stored fat into ketones (Harvard Health Publishing). This process is called ketosis. On average, ingesting no more than 50 grams of carbohydrates a day (Harvard Health Publishing) will keep your body in this fat-burning state.

Now that you have a little background on what ketosis and the ketogenic diet are, let’s look at what the research is saying in terms of sustained weight loss from this diet. After all, claims of weight loss due to the ketogenic diet seem to be promised all over social media and the news recently. Fortunately, there is a good amount of research out there investigating this way of eating, but are they all significant? Let’s find out.

The Research:

In a 6-month study done by the New England Journal of Medicine, 132 severely obese subjects with a high prevalence of diabetes were randomly assigned to either a low-carb or low-fat diet (Samaha et al, 2003). It was seen that overall, the subjects following the low-carb diet lost more weight. But, the greater weight loss in this group was attributed to a greater reduction in overall caloric intake, not the effect of the macronutrient composition of their assigned diet (Samaha et al, 2003). Total cholesterol, HDL cholesterol (or, the ‘good’ cholesterol), and LDL cholesterol (the ‘bad’ cholesterol) did not change significantly throughout the duration of the study. As far as blood glucose levels, the low-carb group showed a greater reduction in these levels, however it was limited to diabetic subjects. There was no significant change in the levels of those who were non diabetic on either diet (Samaha et al, 2003). Neither group showed changes in blood pressure, and it was noted that it is unknown if there are true benefits to a low-carb diet past the 6-month mark (Samaha et al, 2003).

A 2008 study done by the American Journal of Clinical Nutrition looked at the effects of a ketogenic diet on hunger, appetite and weight loss in 17 men over one month (Johnstone et al, 2008). The subjects were randomly assigned to either a ketogenic diet (4% carbohydrate) or a medium-carbohydrate diet (35% of their total calories). It was found that although weight loss was significantly greater with the low-carb diet than with the medium-carb diet, it was reported that much of it was due to a difference in water loss with the ketogenic diet (Johnstone et al, 2008). A major component of this study was to analyze daily hunger scores and satiety between the two diets. It was seen that those following a ketogenic diet did report less hunger compared to the other diet, however these reports were only analyzed after one week and six weeks (Johnstone et al, 2008). Note that the sample size of this study was quite small.

In another study published by The American Journal of Clinical Nutrition, authors investigated weight loss and biomarker change in subjects following a ketogenic diet versus, you guessed it, a non-ketogenic diet. Biomarkers included, but was not limited to, fat mass, age, percentage body fat, waist circumference, wast:hip ratio, etc. Ultimately, it was seen that the ketogenic diet did not offer any clear metabolic advantage over the non-ketogenic diet (Johnston et al, 2006). This study also analyzed hunger levels in the subjects and showed that these ratings did not differ significantly between both diet groups (Johnston et al, 2006).

One of the strongest studies I found was conducted over one year and was a multi-center, controlled trial composed of 63 obese participants. Instead of just looking at high-carb versus low-carb diets, subjects were randomly assigned to either a low-carb, high-protein, high-fat, high-carb or a low-fat (what they called a ‘conventional’) diet (Foster et al, 2003). The low-carb diet resulted in greater weight loss compared to the conventional diet at the six-month mark, however the differences were not significant at one year.

The Take-Away:

The message from all of these studies remains the same. As with many fad diets out there, weight loss may be seen by following the regimen short-term. Many times these diets are lower in calories, which will ultimately lead to weight loss. Americans often want that ‘quick-fix’ but several factors may keep one from following a diet for longer periods of time. It remains unclear as to why exactly weight loss was only significant up to six months. These studies prove that longer and larger studies on the ketogenic diet are needed to truly determine the effectiveness of it.

References:

(1) “Atkins Diet: How It Works, Health Benefits, Plus Precautions." Dr. Axe, https://draxe.com/atkins-diet/. Accessed 28 Feb. 2018.

(2) Campos, Marcelo. "Ketogenic diet: Is the ultimate low-carb diet good for you?." Harvard Health Publishing: Harvard Medical School, Harvard Health Publishing, 27 July 2017, https://www.health.harvard.edu/blog/ketogenic-diet-is-the-ultimate-low-carb-diet-good-for-you-2017072712089. Accessed 28 Feb. 2018.

(3) Samaha, Fredrick, Nayyar Iqbal, Prakash Seshadri, Kathryn Chicano, and Denise Daily. "A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity." The New England Journal of Medicine, vol. 343, 27 May 2003, pp. 2074-81. Accessed 28 Feb. 2018.

(4) Johnstone, Alexandra, Graham Horgan, Sandra Murison, David Bremner, and Gerald Lobley. "Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum." American Journal of Clinical Nutrition, vol. 87, 2008. Accessed 28 Feb. 2018.

(5) Johnston, Carol, Sherrie Tjonn, Pamela Swan, Andrea White, and Heather Hutchins. "Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets." The American Journal of Clinical Nutrition, vol. 83, no. 5, 1 May 2006, pp. 1055-61, doi:10.1093, https://academic.oup.com/ajcn/article/83/5/1055/4649481. Accessed 1 Mar. 2018.

(6) Foster, Gary, Holly Wyatt, James Hill, Brian McGuckin, and Carrie Brill. "A Randomized Trial of a Low-Carbohydrate Diet for Obesity." The New England Journal of Medicine, vol. 348, May 2003, pp. 2082-90, doi:10.1056, www.nejm.org/doi/full/10.1056/NEJMoa022207. Accessed 1 Mar. 2018.

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