In Wednesday’s newsletter, we asked you for your opinion of the keto diet, and got the above-depicted, below-described set of responses:

• About 45% said “It has its benefits, but they don’t outweigh the risks”
• About 31% said “It is a good, evidence-based way to lose weight, be energized, and live healthily”
• About 24% said “It is a woeful fad diet and a fast-track to ruining one’s overall health”

So what does the science say?

First, what is the ketogenic diet?

There are two different stories here:

• Per science, it’s a medical diet designed to help treat refractory epilepsy in children.
• Per popular lore, it’s an energizing weight loss diet for Instagrammers and YouTubers.

Can it be both? The answer is: yes, but with some serious caveats, which we’ll cover over the course of today’s feature.

The ketogenic diet works by forcing the body to burn fat for energy: True or False?

True! This is why it helps for children with refractory epilepsy. By starving the body (including the brain) of glucose, the liver must convert fat into fatty acids and ketones, which latter the brain (and indeed the rest of the body) can now use for energy instead of glucose, thus avoiding one of the the main triggers of refractory epilepsy in children.

See: The Ketogenic Diet: One Decade Later | Pediatrics

Even the pediatric epilepsy studies, however, conclude it does have unwanted side effects, such as kidney stones, constipation, high cholesterol, and acidosis:

Source: Dietary Therapies for Epilepsy

The ketogenic diet is good for weight loss: True or False?

True! Insofar as it does cause weight loss, often rapidly. Of course, so do diarrhea and vomiting, but these are not usually held to be healthy methods of weight loss. As for keto, a team of researchers recently concluded:

❝As obesity rates in the populace keep rising, dietary fads such as the ketogenic diet are gaining traction.

Although they could help with weight loss, this study had a notable observation of severe hypercholesterolemia and increased risk of atherosclerotic cardiovascular disease among the ketogenic diet participants.❞

~ Dr. Shadan Khdher et al.

Read in full: The Significant Impact of High-Fat, Low-Carbohydrate Ketogenic Diet on Serum Lipid Profile and Atherosclerotic Cardiovascular Disease Risk in Overweight and Obese Adults

On which note…

The ketogenic diet is bad for the heart: True or False?

True! As Dr. Joanna Popiolek-Kalisz concluded recently:

❝In terms of cardiovascular mortality, the low-carb pattern is more beneficial than very low-carbohydrate (including the ketogenic diet). There is still scarce evidence comparing ketogenic to the Mediterranean diet.

Other safety concerns in cardiovascular patients such as adverse events related to ketosis, fat-free mass loss, or potential pharmacological interactions should be also taken into consideration in future research.❞

~ Dr. Joanna Popiolek-Kalisz

Read in full: Ketogenic diet and cardiovascular risk: state of the art review

The ketogenic diet is good for short-term weight loss, but not long-term maintenance: True or False?

True! Again, insofar as it works in the short term. It’s not the healthiest way to lose weight and we don’t recommend it, but it did does indeed precipitate short-term weight loss. Those benefits are not typically observed for longer than a short time, though, as the above-linked paper mentions:

❝The ketogenic diet does not fulfill the criteria of a healthy diet. It presents the potential for rapid short-term reduction of body mass, triglycerides level, Hb1Ac, and blood pressure.

Its efficacy for weight loss and the above-mentioned metabolic changes is not significant in long-term observations.❞

~ Ibid.

The ketogenic diet is a good, evidence-based way to lose weight, be energized, and live healthily: True or False?

False, simply, as you may have gathered from the above, but we’ve barely scratched the surface in terms of the risks.

That said, as mentioned, it will induce short-term weight loss, and as for being energized, typically there is a slump-spike-slump in energy:

1. At first, the body is running out of glucose, and so naturally feels weak and tired.
2. Next, the body enters ketosis, and so feels energized and enlivened ← this is the part where the popular enthusiastic reviews come from
3. Then, the body starts experiencing all the longer-term problems associated with lacking carbohydrates and having an overabundance of fat, so becomes gradually more sick and tired.

Because of this, the signs of symptoms of being in ketosis (aside from: measurably increased ketones in blood, breath, and urine) are listed as:

• Bad breath
• Weight loss
• Appetite loss
• Increased focus and energy
• Increased fatigue and irritability
• Digestive issues
• Insomnia

The slump-spike-slump we mentioned is the reason for the seemingly contradictory symptoms of increased energy and increased fatigue—you get one and then the other.

Here’s a small but illustrative study, made clearer by its participants being a demographic whose energy levels are most strongly affected by dietary factors:

The glycaemic benefits of a very-low-carbohydrate ketogenic diet in adults with Type 1 diabetes mellitus may be opposed by increased hypoglycaemia risk and dyslipidaemia

The ketogenic diet is a woeful fad diet and a fast-track to ruining one’s overall health: True or False?

True, subjectively in the first part, as it’s a little harsher than we usually go for in tone, though it has been called a fad diet in scientific literature. The latter part (ruining one’s overall health) is observably true.

One major problem is incidental-but-serious, which is that a low-carb diet is typically a de facto low-fiber diet, which is naturally bad for the gut and heart.

Other things are more specific to the keto diet, such as the problems with the kidneys:

The Relationship between Modern Fad Diets and Kidney Stone Disease: A Systematic Review of Literature

However, kidney stones aren’t the worst of the problems:

Is Losing Weight Worth Losing Your Kidney: Keto Diet Resulting in Renal Failure

We’re running out of space and the risks associated with the keto diet are many, but for example even in the short term, it already increases osteoporosis risk:

❝Markers of bone modeling/remodeling were impaired after short-term low-carbohydrate high-fat diet, and only one marker of resorption recovered after acute carbohydrate restoration❞

~ Dr. Ida Heikura et al.

A Short-Term Ketogenic Diet Impairs Markers of Bone Health in Response to Exercise

Want a healthier diet?

We recommend the Mediterranean diet.

See also: Four Ways To Upgrade The Mediterranean

(the above is about keeping to the Mediterranean diet, while tweaking one’s choices within it for a specific extra health focus such as an anti-inflammatory upgrade, a heart-healthy upgrade, a gut-healthy upgrade, and a brain-healthy upgrade)

Enjoy!