Keto diet facts - An expert nutrition review

There are many structured eating plans available for weight loss. Want to learn important keto diet facts? This post describes the ketogenic diet - what it is, the pros and cons, and whether or not it is effective for weight loss.

Keto diet facts and history

The ketogenic diet is a more recent entry on the weight loss scene, but it has been around for much longer. Hundreds of years ago, people recognized that fasting helped control seizures, such as from epilepsy. But fasting isn't a realistic long-term solution. Eventually, the ketogenic diet evolved to mimic the metabolic aspects of fasting. It's still used, especially for children who do not respond well to medications that control seizures. One undesirable side effect of the diet on children is weight loss. Careful attention must be paid to children on this diet to be sure they maintain enough food intake to support growth and maintain weight. It's that undesirable side effect that brought the ketogenic diet to the attention of dieters. Now it's being promoted to treat obesity.

This extremely restrictive diet creates a metabolic state called ketosis. Severe carbohydrate restriction shifts metabolism to fat burning for energy needs. People with Type 1 diabetes are familiar with ketosis, as it signals insufficient insulin and poor glucose control, forcing fat metabolism for energy needs. The by-products of so much fat metabolism are ketones, which are quickly flushed out by the kidneys to prevent toxic build-up. One other side effect: appetite suppression, is a benefit for dieters. You end up eating fewer calories than you need, and the deficit leads to weight loss, as fat is preferentially burned for energy needs.

Keto tips for beginners

The ketogenic diet must be extremely restrictive to push metabolism into ketosis. The approximate percentage of calories is:

• 70-75% fat
• 20% protein
• 5-10% carbohydrate

All typical carbohydrate foods are prohibited, aside from certain vegetables in small amounts.

Contrary to popular belief, this is not a high protein diet. At 20% of calories, protein is actually limited to a modest amount. For example, for a 1600 calorie daily intake, protein would be 80 grams, or about 25 - 30 grams for each of 3 meals. That's roughly a 4 oz portion of meat, not a giant steak. And protein foods must be restricted to leave room for high fat foods.

The permitted food list is very specific, and most of the foods are high-fat:

• Cream
• Full-fat cheeses
• Cream cheese
• Sour cream
• Eggs
• Red meat, poultry or fish
• Bacon
• Vegetable oils
• Avocado
• Nut butter and nuts, in restricted amounts, due to the carbohydrate content
• Very small amounts of low-carb vegetables like greens, broccoli, cauliflower, mushrooms, cucumbers, peppers, zucchini and tomato.

Let's say you want to keep the number of carb grams at 5% of calories. The 1600 calorie diet would allow for 20 grams of carbs. If you ate 2 tablespoons of peanut butter, which has carbs, you could add 1/2 an avocado and 1 cup cooked spinach. That's it for carbs. All of your other foods would have to come from the list above.

Note: Many people choose to track net carbs, meaning total carbs minus dietary fiber. This allows more vegetable servings in the plan.

Pros

• The obvious benefit for dieters is that, if you stick with the diet long enough, you go into ketosis and start burning more fat and losing weight. Ketosis takes some time to develop; you don't go into that state on Day 1 or even Day 3 of the diet. Urine ketone sticks can be used to test your urine for ketones; some keto diet plans advise this testing to monitor ketosis.
• Hunger suppression is a clear benefit for dieters who find it hard to stick to standard low calorie diets.
• If you are overweight and at risk for Type 2 diabetes, hypertension or heart disease, and you do lose significant weight, your risk may decrease accordingly, despite the extremely high-fat intake.

Cons

• Nutrient imbalances: the diet is unbalanced, lacking in many nutrients. Potential problem nutrients are calcium, magnesium, potassium. vitamin C, vitamin A, vitamin D, B vitamins and fiber. It is also low in carotenoids, antioxidants and probiotics.
• It should not be considered a long-term diet because it is unbalanced. Sure, you can take vitamin and mineral supplements. Still, no supplement can replace naturally occurring plant fiber, antioxidants, polyphenols, probiotics and prebiotics. For example, you could take a probiotic supplement. However, with nothing to live on, those expensive probiotic bacteria will simply die off.
• Extreme food restrictions. The extremely restrictive nature of this diet makes it difficult to have a social life. You cannot eat meals normally served in restaurants or at other people's homes. It can be very isolating, as you'll need to prepare all your meals and snacks at home.
• Body odor. Ketones, the by-products of ketosis, are the same chemicals used in nail polish remover. In fact, one sign of diabetic ketoacidosis is breath that smells like nail polish remover. If you are not around people much, this may not be a concern. Some couples go on the diet together, making meal preparation and any odor issues less burdensome.
• Boredom. All that fatty food, day after day gets old. No crunch or refreshing flavor of fruit, not to mention all the foods people enjoy daily, from oatmeal to pizza. All off-limits. How much sour cream or avocado can you stand?
• Transitioning back to normal food. Few people would keep up a ketogenic diet indefinitely, because of the boredom and social isolation, if not the nutritional problems. But at the moment, there is little agreement on how to transition back to more normal food intake. Adding carbs back will inevitably change metabolism, resulting in some weight regain, mostly water weight at first. That can be discouraging.
• Rebound effect. As with any extremely restrictive diet, the tendency is to go overboard and treat yourself to all the foods you've been missing for so long. In which case, you might find yourself regaining more than just a few pounds of water weight. If you go back to your previous weight gain-promoting ways, you'll regain all the weight. Not a good plan. So you need some structure to your return to normal food.
• Complications for existing medical conditions. No one with an existing medical condition should start this diet without first consulting a physician and also understanding the keto diet facts. People with diabetes who take insulin (or any medication with a high risk for hypoglycemia) need to discuss safety issues with their physician before starting this plan. You may be advised to follow the diet intermittently. There are some reports of loss of menstrual periods and possible infertility in women who follow this diet. However, there is no solid evidence that this is caused by the ketogenic diet as opposed to mere caloric restriction and weight loss. If you follow this diet and develop amenorrhea, you should stop and consult a medical provider.

Cost

A ketogenic diet isn't going to cost that much more or less than your normal groceries. You aren't expected to purchase special, branded meals or products. All foods are available at any supermarket. Working with a registered dietitian on diet planning and follow up would add modestly to the overall cost.

Summary

Does it work?

Yes, it works if you successfully transition to ketosis and stick with the diet long enough to lose weight.

Who would most benefit from this diet?

People desiring weight loss who have not had good success sticking to more liberal low calorie diets may like the keto plan. Clear restrictions decrease options. Sometimes people are relieved to just have a simple list of what they can eat, omitting choice from the weight loss equation. Also, people who are motivated by seeing the number on the scale go down more quickly than a pound per week might like this diet. So, in general, people who are motivated by results and who do better with less choice, and who don't mind the socially isolating nature of this diet might benefit.

Is it viable long term?

No, it is not. It's nutritionally unbalanced, and supplements cannot make up for all those deficiencies. Since weight loss is a new application for this diet, and few people stick to it long term, there is little data on what a ketogenic diet might mean for future health.

Do I like this diet?

I wouldn't go on a ketogenic diet myself, but I realize many people have found weight loss success with it. My advice is to work with a professional who understands the keto diet facts and can help you successfully follow it, perhaps short-term, and then transition off of it after your weight goals are achieved.

Resources

Ketogenic diets are now being used for various brain diseases. The Charlie Foundation provides information about ketogenic therapy for seizures. The website has recipes and information that would be useful to people on ketogenic diets for weight loss. Medical News Today has some keto diet facts.

Other MyNetDiary articles on the Keto diet:
Should I go keto? 5 Facts you need to know before taking on this diet
These are the top 10 keto foods you should include if you're on the diet

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This article was reviewed and updated by Brenda Braslow, MS, RD, LD, CDE on May 1, 2020

Weight Loss->Diets