The Ketogenic Diet isn’t just the latest fad diet—it’s actually been around since 1924, when it was developed by Mayo Clinic Dr Russell Wilder. Originally it was developed for the treatment of epilepsy—and I’ll get into my theory of why this works in a bit.

What the Ketogenic Diet Is

The Ketogenic Diet is all about macronutrient ratios: it’s high fat, low protein, and low carbohydrates. Standard percentages are about 75% fat, 20% protein, and 5% carbs, though there is a high protein version in which the carbs stay the same, there’s 60% fat, 35% protein.

How the Ketogenic Diet Works for Weight Loss

Your body’s preferred energy source is glucose (sugar). That’s why sugar tastes so good to us: it has a very high glycemic index, meaning the body can turn it into glucose quite rapidly. Carbohydrates also have a very high glycemic index: the more processed the carb, the higher the glycemic index becomes.

But when glucose isn’t available, your body will instead break down its fat stores and turn them into ketones. Most cells in your body can use ketones for fuel as a glucose substitute—including your brain, since ketones readily cross the Blood Brain Barrier.

How you get there:

Foods to Avoid: anything with a high glycemic index, including actual sugar (desserts, juice, sodas, candy, etc), or anything white (rice, pasta, cereal). On this diet, fruit is virtually eliminated as well, except for occasional berries. Beans, legumes, and root vegetables are also too starchy and thus, too high on the glycemic index to ensure ketosis.

Allowable foods include any kind of meat, fish, eggs, dairy products (butter, cream, and cheese), nuts and seeds, healthy oils like coconut and avocado oil and extra virgin olive oil, avocados, leafy greens, cruciferous veggies, and nightshades (tomatoes, onions, peppers, etc).

Supplements that help encourage ketosis are MCT oil (Medium Chain Triglycerides), which convert to ketones more efficiently than longer chain fatty acids do, and extra coconut oil.

Health Benefits

Because the diet is so effective for weight loss and insulin resistance, it also greatly reduces cardiovascular risk factors.

As mentioned in the introduction, the Ketogenic Diet was originally developed for seizures. I suspect this works because ketones act as antioxidants in the brain, dampening down excitotoxicity.

Less excitotoxicity also be why the diet works for Traumatic Brain Injury (TBI) and for Alzheimer’s Disease, though I suspect in the case of the latter, it also has to do with the low glucose levels. In some circles, Alzheimer’s is now being called “Type 3 Diabetes.”

Probably because cancer feeds primarily on sugar (PET scans measure highly metabolic tissue based on sugar consumption, after all), there is evidence that the ketogenic diet is effective for malignant brain tumors. 1, 2.

Nutrient Deficiencies

It’s possible to develop nutrient deficiencies on this diet. The big ones to look out for are sodium, potassium, and magnesium.

All of these electrolytes are regulated by the kidneys. One of insulin’s lesser known functions is that it encourages the kidneys to retain sodium. The ketogenic diet drops insulin very significantly, though—so even consuming animal products which are naturally high in sodium, and salting food to taste might not be enough to counteract this effect.

When insulin levels drop, sodium drops, and when sodium drops, you pee more (because water follows sodium). This means you’re likely to lose other electrolytes along with sodium, including magnesium (a very common nutrient deficiency) and potassium. Potassium is primarily found in avocados, bananas, potatoes, apricots, and prunes—and of that list, only avocados are allowed on the diet, making it potentially difficult to maintain levels.

The best way to deal with these potential deficiencies is to supplement with them.

Adverse Effects of the Ketogenic Diet

Probably due to the low fiber content, constipation is a common problem with the ketogenic diet. Drinking plenty of water can combat this, as can increasing the veggies or adding in a fiber supplement.

My Overall Take on the Ketogenic Diet

While the side effects of electrolyte deficiencies and constipation can be dealt with easily enough, I’m not a big fan of any diet that is overly restrictive and/or creates imbalances, unless there’s a good reason for it.

I would certainly recommend giving the Ketogenic Diet a try in any case of excitotoxicity, though, including Multiple Chemical Sensitivity (MCS), or almost any neurological disorder. (There are also certain tests that will directly or indirectly measure excitotoxicity, including the Urinary Organic Acid (OAT) test, and genetic testing including 23 & Me, which can measure the predisposition. That way you can tell if excitotoxicity plays a role in your particular condition.)

For weight loss, I’d probably recommend a less restrictive low carb, high protein diet before this one, because it’s easier to stick to and wouldn’t have the deficiency problems that this one might. But in resistant cases in which the weight just doesn’t want to budge, this is certainly an effective approach to try.