The Ketogenic Diet: Fabulous or Fad?

By Stephen T. Sinatra, M.D., F.A.C.C., F.A.C.N., C.N.S., C.B.T.

If you haven’t heard about the ketogenic diet, you probably just got back from vacationing on Mars…

In all seriousness, though, “keto” dieting has taken the world by storm. Celebrities and fitness experts swear by its weight loss powers, athletes say it boosts their performance, and patients with Alzheimer’s, epilepsy, and other serious diseases have been able to use the ketogenic diet to treat, halt progression, or even reverse their conditions.

Even crazier, all of these claims about the ketogenic diet may actually be valid.

What Is the Keto Diet?

While it may seem like the latest weight loss fad, the ketogenic diet actually has a 100-year-long history.

In the 1920s, physicians used a ketogenic diet to treat epilepsy in children. Back then, researchers knew that extreme hunger (or even starvation) decreased the incidence of seizures. But instead of forcing kids to go hungry in an effort to treat their epilepsy, they created a diet to mimic the process that was reducing the seizures in the first place: ketosis.

During ketosis, the body uses fat for energy. It doesn’t normally, though. The body’s preferred fuel source is glucose, which is the easiest molecule for it to convert into energy. This glucose comes from dietary carbohydrates.

It’s an efficient system, especially for those who eat well-balanced diets with healthy ratios of fats, carbs, and proteins. But let’s get real for a second… Many (dare I say, most) people in this country follow the “standard American diet,” which as far too rich in refined carbs and sugars. Such high-carb diets lead to the overproduction of glucose. There are a few things that happen when too much glucose is coursing through the blood. The body uses whatever glucose it needs for energy. The remaining glucose then gets stored in the liver as glycogen. If there’s any that’s left after that, the body converts it and stores it as fat. (And you know what comes next: weight gain, then diabetes, heart disease, and other conditions related to obesity.)

With the ketogenic diet, you dramatically lower your intake of carbs and increase your intake of fats. As a result of this carb-limiting diet, the body no longer has the glucose it needs for energy. So it seeks out an alternative energy source—and that source is fat.

Fat starts to get broken down into ketone bodies (ketones for short), which generate energy and continue to do so until carbohydrates are reintroduced and glucose can once again be used. If that doesn’t happen, it will keep burning fat reserves indefinitely.

Benefits of the Ketogenic Diet

Research clearly shows that the ketogenic diet can be effective for weight loss and, as mentioned earlier, treatment of some types of seizures. But that’s not all. It shows promise with other neurological diseases like Alzheimer’s, as well as diabetes.

Weight loss is perhaps the main reason people want to give the ketogenic diet a try. And for many, it really works. The process of ketosis melts fat away as the body converts it to ketones, and noticeable results can often be seen within a week. The process of ketosis also happens to decrease appetite, which accelerates weight loss even more.

One study followed 83 obese patients who took part in a 24-week ketogenic diet. Not only did they lose weight, their LDL cholesterol and triglycerides significantly decreased, and their beneficial HDL cholesterol went up.

In a more recent study of 19,036 obese patients on a ketogenic diet, 15,444 experienced impressive weight loss (“a rapid 10% weight loss, 57% of which was fat mass”), with no major adverse effects. The researchers wrote that the diet is “safe, fast, inexpensive, and has good one-year results for weight maintenance.”

People who are overweight and have diabetes may also benefit from going keto. In a 24-week trial of 363 obese participants (102 of whom had type 2 diabetes), researchers wanted to see how a ketogenic diet compared to a low-calorie diet when it came to several measures, including weight, body mass index, waist circumference, blood glucose levels, hemoglobin, cholesterol, and triglycerides.

While both diets improved markers, the keto group saw far greater changes. The researchers concluded, “This study shows the beneficial effects of a ketogenic diet over the conventional low-calorie diet in obese diabetic subjects. The ketogenic diet appears to improve glycemic control…”

The keto diet also shows potential for slowing the progression of Alzheimer’s. For one, ketones appear to be neuroprotective, helping to prevent cognitive decline and degeneration in an aging brain. Among other benefits, ketosis can boost the activity of the antioxidant glutathione peroxidase in the hippocampus.

In an animal study, ketosis prevented amyloid beta plaques—a hallmark sign of Alzheimer’s. And in a trial of 152 people with mild to moderate Alzheimer’s, those who took an oral compound that induced ketosis showed substantial improvements on cognition tests by day 45, compared to the placebo group.

This research is still preliminary, but considering all the Alzheimer’s treatments available right now do little to stop disease progression, ketosis may provide the hope that these patients need.

Keto Diet Foods

A classic ketogenic diet involves completely eliminating all sugars (honey, maple syrup, agave, white/brown sugar, molasses, coconut sugar, etc.), all starchy veggies (tubers like white and sweet potatoes, and root vegetables such as beets, carrots, etc.), all grains and legumes, and most fruit. (It should also go without saying that all prepared and processed foods are no-nos.)

What’s left? Lots of fat, moderate protein, and a stingy amount of low-glycemic carbs. That translates to about 75% of calories from fats, 20% from proteins, and the remaining 5% or less from carbs. (Depending on body weight, this typically amounts to about 20–60 grams of carbs per day.)

Here’s a rundown of the allowable keto diet foods:

  • Meats: beef, lamb, pork, veal, venison, poultry, fowl, seafood, eggs
  • Leafy green vegetables: spinach, kale, collard greens, lettuce, endive, bok choy, arugula, etc.
  • Above-ground vegetables: cauliflower, broccoli, eggplant, cucumber, green beans, etc.
  • Coconuts, nuts and seeds, flours and oils made from nuts/seeds; nut butters
  • Avocados and low-glycemic berries (raspberries, blueberries, blackberries, etc.)
  • Healthy oils: olive, avocado, coconut, flaxseed, grapeseed, hempseed, and macadamia
  • Full-fat dairy: hard cheeses, Greek yogurt, and grass-fed butter
  • Full-fat, unsweetened dairy substitutes: coconut, almond, cashew, and soy milk
  • Low-carb sweeteners: stevia, monk fruit, erythritol

Drawbacks of the Ketogenic Diet

While I’m sure you’ll find many nutritionists and experts warning about dangers of the keto diet, I don’t really think there’s anything too harmful about it—as long as the fats you eat are primarily the healthy monounsaturated variety and you don’t go overboard on saturated fats. I would also make sure to eat only grass fed meat and dairy products, and free range or organic poultry and eggs to avoid GMOs and pesticides.

There are a few of the side effects to be aware of, though:

  • Frequent urination: The first few days of starting the ketogenic diet, as your body burns through all your stored glucose, you release a lot of water and excess sodium.
  • Hypoglycemia: Low blood sugar is common the first few days as well, especially for people who are used to eating a lot of carbohydrates. Dizziness, tiredness, shakiness, and hunger are symptoms of hypoglycemia, but they eventually subside once the body adjusts.
  • “Ketosis flu”: Many people experience flu-like symptoms the first three or four days of starting the keto diet. This also subsides.
  • Digestive issues: Constipation or diarrhea can occur due to the drastic change in macronutrient ratios. To make sure you’re getting enough fiber, eat lots of “allowable” vegetables and consider adding a fiber supplement like psyllium husk powder.
  • Bad breath: Acetone is one of the ketones created during ketosis. It definitely has a distinct odor that many find unpleasant, but it’s a good sign your body is in full-on fat-burning mode. Most keto dieters report their bad breath going away after a few weeks.

If there’s any concern I have about going keto, it’s this…

One of the most important characteristics of any diet or eating plan is not its ability to help you lose weight…because in reality, any diet promotes weight loss, especially in the short term. It’s the sustainability of the diet…meaning, is it a plan that you can easily follow for the rest of your life, and enjoy and thrive on? Does it provide all the nutrients you need to stay healthy? Does it help you not only maintain a decent weight, but also excellent heart health? While some research has shown that the keto diet is safe and sustainable, I’m not totally convinced.

Altering your macronutrient ratio so drastically is really hard to do…and it’s even more difficult to keep it up for months at a time. Can you imagine never ever having a strand of spaghetti, a banana, or a glass of wine again? If you’re a follower of strict keto diet, that’s your life.

This is why I’m such a proponent of the Pan-Asian Modified Mediterranean Diet (PAMM), which is a blend of the best of traditional Asian and Mediterranean dietary approaches.

The PAMM diet consists of a healthy, balanced ratio of fats, low-glycemic carbohydrates, and lean proteins—and it even allows for a glass of wine or occasional bowl of pasta, if desired. You never feel deprived, and for that reason alone, PAMM is extremely easy to follow indefinitely.

With that said, though, I don’t see any major reason to not give the ketogenic diet a try for a few weeks or months if you’re really struggling with your weight. (If you want to try it to help resolve or treat a serious health issue like epilepsy or Alzheimer’s, I highly recommend not going it alone and instead working with a doctor who’s knowledgeable in this area.)

My colleague and friend, Dr. Dan Pompa, is a strong believer in a “diet variation” strategy, where you adopt a keto diet for a few months, then add more starchy veggies and fruits back into the program (while continuing to avoid grains and refined sugars), then returning to keto. In his experience, the diet variations trigger metabolic shifts which result in weight loss.

And, if the very strict classic keto diet is too much for you, even a modified version—40% of calories from fat and 30% from both carbs and protein—has been shown to aid in weight loss. (Even better, a modified keto diet is a much more sustainable diet to follow long term.)

Finally, if you’re reading this and thinking, “Nope, Dr. Sinatra, the ketogenic diet is definitely not for me,” but you’re still curious about the potential benefits of ketosis, try intermittent fasting. As I mentioned earlier, “starving” for short periods of time puts the body into ketosis. With intermittent fasting, you’re not restricting any food groups; you’re simply eating in a short 8-hour window during the day (typically between noon and 8pm), and avoiding food the rest of the time. Lots of research praises intermittent fasting for weight loss and blood sugar control.

Whatever you choose to do, don’t lose sight of the big picture: Your health. If you look and feel absolutely fantastic on any particular diet, then it’s probably the right one for you. But if you look and/or feel sluggish, sick, and just plain terrible, then your body is telling you loud and clear that you aren’t giving it something it needs. It’s then time to reevaluate and try something new.


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© Stephen Sinatra, MD. All rights reserved.

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