America has a new (old) fad diet. Have you heard of it?
The keto diet (short for ketogenic) is a high-fat, adequate-protein, low-carbohydrate diet. It is essentially the Atkins diet of the 2000s, but it dates back to the 1920s, when it was used to treat children with epilepsy.
The goal of a keto diet is to get at least 70 percent of your calories from fat, no more than 25 percent of calories from protein and only 5 to 10 percent from carbohydrates. For most people, that means restricting your carbohydrate intake to below 50 grams a day.
If you’re a breakfast taco fan like me, two tacos will put you at your daily carbohydrate limit, and don’t even think of putting potatoes in there! Half a cup of roasted potatoes will send you over the 50-gram limit. To further put that number of carbs into perspective, the following contain about 15 grams of carbohydrates: one slice of bread, 1/3 cup of rice, one cup of milk, 15 grapes, half of a large banana and a 12-ounce Bud Light (beers with higher alcohol will most certainly contain much more than 15 grams).
The impetus for such a carbohydrate restrictive diet was therapeutic in nature. The diet first started nearly 100 years ago when doctors found that when epileptic children switched to a strict all-fat diet, the brain adapted its fuel source and the children had fewer seizures. The ketogenic diet is used to this day to help treat epilepsy, but over the past year or so, millions of everyday eaters have flocked to it for its purported health weight loss benefits.
The goal of this diet is to force the body to burn fat instead of carbohydrates as fuel, which produces ketones. Our body and brain then use these ketones to fuel our cells. The increase in ketones puts the body in ketosis, a natural process the body initiates to help us survive when food intake is low.
What does one eat on a keto diet? It’s easier to start with what you don’t eat. No bread, fruit, starchy vegetables (such as potatoes or beans), cookies, candy, ice cream, pizza, sandwiches, rice, cereal, oatmeal, smoothies, beer, protein bars. … Basically, most food is off limits.
That leaves us with full-fat dairy (cheese, plain yogurt, butter), greens such as spinach and kale, nuts and seeds, oils, avocados and meat.
You can’t deny the fact that people will lose weight on the keto diet. First of all, you’re eliminating a major food group. When you do that, you limit your food options and most likely your food intake, so it’s not rocket science that you’ll likely lose weight.
Second, most people on a low-carb diet tend to increase their protein intake in the absence of carbohydrates. There is some evidence that consuming higher amounts of protein may result in some weight loss benefits. Third, the body retains water when you eat carbohydrates. Glycogen is the storage from of glucose, what your body uses as fuel when you eat carbohydrates. Every gram of glycogen in your body is bound to water.
When you don’t give your body any carbohydrates for energy, you burn through glycogen stores and the water attached to them as well. You don’t actually get rid of any fat in your body in the beginning. If you were to eat a high-carbohydrate meal, the water weight would quickly return.
Most studies on the keto diet are short term and often have very small sample sizes. Some of them back up the short-term benefits related to weight loss. However, there are some potential dangers of following a keto diet long term.
One concern is the maintenance and potential loss of muscle mass. This is because when we eat carbohydrates we produce insulin, which promotes muscle growth. Some research has shown that even if your protein intake remains constant, a low-carbohydrate diet may promote muscle loss.
Constipation is one of the most common side effects of following a keto diet. This is because a low-carbohydrate diet means you’re missing out on fiber-rich grains, fruits and certain vegetables.
With the high intake of fat, there is some concern about the high intake of cholesterol. A study using the keto diet as a form of treatment for epileptic seizures in children found that after six months of administering the diet, triglyceride levels increased, total cholesterol levels increased and HDL and LDL increased. These results suggest that over time, a keto diet may lead to an increased risk of high cholesterol and triglycerides. If heart disease runs in your family, you may want to consult your doctor before trying this diet.
Another concern is the strain on our kidneys with the higher levels of protein. Though a keto diet is made up of moderate protein, people following a low-carbohydrate diet will often consume more protein because of the lack of carbohydrates, and protein usually goes hand in hand with fat. It is highly recommended that you consult your doctor and assess your kidney function before going on this diet, especially if you have existing kidney problems.
Lastly, strict dietary restriction means we may be missing out on crucial vitamins and minerals. With the keto diet, major minerals that are missed include sodium, potassium and chloride. Other vitamins that might be missed out on include vitamin D, calcium, magnesium, selenium and zinc. You might want to consider taking supplements and a multivitamin.
That’s a lot of potential downsides, but my biggest concern about the keto diet is that it’s another diet that is hard to maintain long term. If you like traveling and trying new things, going to restaurants, celebrating a friend’s birthday with cake or cocktails, you’re not going to enjoy planning every meal ahead and taking food with you everywhere.
Like every other diet out there, most people can usually do it for a few days or weeks before falling off the wagon, especially when you can’t eat things that are as familiar as an apple. Diets tend to be unsustainable for long periods of time, let alone the rest of your life. Dieting can also put people in a negative state of mind because they now feel guilty for eating “bad foods.” They view themselves as “bad” or “out of control.” And studies show that most people who lose weight on diets regain it, and sometimes more, within a few months or years.
Extreme diets such as the keto diet do not address underlying behavioral and lifestyle issues. People think that once they get to their goal weight they will go back to eating “normally.” But if you got to an undesirable weight by eating “normally” then perhaps you need to work on your definition of a “normal” diet and behaviors surrounding food instead of opting for an extreme diet. I recommend making small but sustainable changes, staying away from anything extreme, and building up small changes over time.
There is one healthy takeaway from the keto diet. In general, incorporating more healthy fats — like nuts and avocados and certain oils — in your diet, without going to extremes, is a good idea for most of us. I am a firm believer in having a good amount of healthy fat in my diet, and many people tend to skimp on that.
Is ketosis is dangerous?
It is important to point out that ketosis is not the same as ketoacidosis, though they sound very similar and are often confused. Ketoacidosis is most common in people with untreated Type 1 diabetes, but it can also occur in those with Type 2 diabetes who no longer produce insulin on their own. Prolonged alcoholism may also lead to alcoholic ketoacidosis.
Ketoacidosis is driven by the body’s lack of insulin, the hormone that brings glucose (blood sugar) into the cells to be used for energy. Without insulin, blood sugar raises to high levels and the body starts to break down fat for energy, which produces acidic ketone bodies. The combination of high blood sugar and high ketone levels can upset the normal acid/base balance in the blood and potentially lead to a coma or even death.
For a person with normal insulin levels who is in ketosis, the level of ketones in the blood never reach the crazy high levels as people experiencing ketoacidosis. So ketosis is generally safe for the average healthy individual.
ABOUT THE AUTHOR
Mary Agnew is a registered dietitian and the nutrition education manager at the Central Texas Food Bank. In this role, she schedules and teaches nutrition education classes throughout the food bank’s 21-county service area. Outside of work, Mary enjoys devoting her time to her pug, Klaus, exploring national parks and finding the best cheeseburger in town. Want to ask Mary a question about food and nutrition? Send an email to email@example.com.