Is the Keto Diet Worth It?

As expected, the arrival of the new year has brought with it a rush of stories on new diet resolutions — along with some serious misinformation about how effective they might be. The “hot new trend” according to many of these stories is the ketogenic diet. There’s a lot of hyperbole in these articles when it comes to keto—sometimes also called the “Silicon Valley diet” or the “bacon and butter diet”—so it’s hard to tell how many people are really doing it and how much of it is just a marketing push. But it’s worth looking into it a bit deeper to see what all the talk is about.

Basically, the keto diet calls for very low consumption of carbs and extremely high consumption of fats. The easiest comparison is with the Atkins diet, although the ketogenic diet is actually much older (dating back to the 1920s). There is some medical precedence that supports keto. It was originally developed not for weight loss, but as a means of controlling epileptic seizures in children. It works like this: when deprived of carbohydrates, the body is forced to burn fat for fuel. Instead of converting carbohydrates to glucose, fats are converted to fatty acids and ketone bodies. Elevated levels of ketone bodies in the blood and brain (a state known as ketosis) leads to a reduction in frequency of epileptic seizures.

And then came Silicon Valley and an obsession with biohacking that’s just a few steps short of the TV series Orphan Black. Already they’ve brought us Soylent, a liquid food replacement, and then the extreme 5:2 fast, and now they’ve latched onto the supposed ancillary benefits of keto. It’s not just about weight loss, they claim; it’s also about sharpened mental acuity and being all you can be.

Of course none of that is proven, and likely never will be. As usual, people will move on to the next fad before any real studies can be conducted.

For now, the New Year’s stories highlighting the keto diet are all about fat burning and weight loss, and some of the claims are extreme. Business Insider and Women’s Health magazine, for example, both say that the keto diet can burn ten times more fat than other diets. Women’s Health additionally claims keto can increase your Resting Metabolic Rate (RMR) by ten times.

Ten times? That’s crazy. Even The Rock at his most active doesn’t burn anywhere near ten times a typical RMR.

It turns out that both of those stories are getting their outlandish numbers from a misreading of one particular recent study: Induced and controlled dietary ketosis as a regulator of obesity and metabolic syndrome pathologies. Authors Madeline K. Gibas and Kelly J. Gibas looked at a small sample of adults already diagnosed with metabolic syndrome (a precursor to diabetes) and compared the results when some participants were put on a ketogenic diet and others were put on a standard American diet (with and without exercise) for ten weeks.

The study did show statistically significant improvements in weight, body fat, and Resting Metabolic Rate for the ketogenic diet group. However, for popular publications to compare these results to “other diets” is unfair, as the control groups in this study were not placed on diets designed to bring about improvements, but rather on a standard American diet.

As for the “ten times” numbers? Those seem to come from a misinterpretation of one line in the study regarding the “slope” of the RMR change for keto participants over the ten week study. In actuality, the keto diet resulted in an RMR increase of perhaps 2.5% and an average decrease in body fat of about 8%.

Those aren’t bad numbers, although similar results could be obtained from any consciously applied healthy diet. And as always, we have to ask a couple of questions. Is the keto diet sustainable? Will the improvements seen on the diet disappear once the diet is over?

To answer the first question: probably not. By all accounts, the keto diet is very difficult to stick to. In order to sustain the condition of ketosis, the diet requires 80–90% of all calories to come from fats, with carbs limited to just 10–15 grams per day. Keto dieters should also consume one gram of protein per kilogram of body weight. Those are very strict conditions that severely limit food choices. For anyone who enjoys eating, choosing a keto diet for weight loss sounds like a quick path to misery.

As for whether any successful results from a keto diet will last, we don’t really have any evidence one way or another. But it’s probably safe to say that in the long term what makes the most difference is what you do every day after the diet is over.

So why not skip the torture and start developing healthy, enjoyable everyday habits instead? The annual list of diets from US News and World Report just put DASH and the Mediterranean diet up top, as usual, and keto in last place.