Most of us who have struggled with weight and health issues have heard of the ketogenic or “keto” diet. I have had several patients recently ask me if I “believe in Keto” as if it were some disreputable underground movement. Opinions about this dietary strategy are all over the map. Countless articles on the internet tell you how good it is while others warn of its dangers. The truth likely lies somewhere in between those extremes. Hopefully this blog post will clear up some of the confusion.
The ketogenic diet was originally a therapeutic diet that has been used since the 1920’s by doctors to treat seizures in children who did not respond to any other therapies. Basically the diet consists of a high percentage of fats with moderate protein and a very low amount of carbohydrates (20-50 grams/day). This is not to be confused with the Atkins diet so popular in the 70’s which was a very high protein diet. The science behind the effectiveness of the keto diet is that in the absence of carbohydrates the liver uses fat to make an alternative source called ketones to fuel the body. Without a heavy load of carbohydrates, the fat storage hormone insulin is reduced and the body can now access its own fat stores to produce the energy it needs throughout the body, including the brain. The use of ketones instead of glucose by the brain is felt to be responsible for the reduction in seizures. Somewhere along the way the ketogenic diet has made its way into the mainstream because while it can be therapeutic for some specific diseases, it can also be can be used to promote weight loss because of the increased fat burning.
So how does a diet that is so high in fat (up to 70%) promote weight loss? At the risk of sounding like a broken record, it is all about how the types of foods we eat impact insulin levels. Simple carbohydrates like sugar, bread, rice, pasta and potatoes cause an increase in insulin levels in order to lower the blood sugar. Protein has a lesser effect on insulin levels and fats have no effect at all. You should recall from an earlier blog post that insulin is a fat storage hormone. The carbohydrates we eat must be immediately used as fuel or insulin will cause the body to store it as fat. Fat is our body’s natural back up fuel supply. The problem is that we rarely use up all the fuel we take in from processed carbohydrates and it stays with us in the form of increasing body fat. This is why a diet that is low in carbohydrates has been documented to result in significant weight loss, at least in the short term. The ketogenic diet takes the standard low carbohydrate diet to the next level by severely limiting starchy carbohydrates and encouraging that most of one’s daily intake come from fats.
Proponents of the ultra low carbohydrate ketogenic diet tout these documented benefits:
1. Diminished hunger. One of the drawbacks to a high carbohydrate diet is the incessant hunger. An eating plan high in fats will help you stay satisfied because it is less likely to spike insulin levels to reduce your blood sugar and trigger hunger. This diminished hunger makes the ketogenic eating strategy much easier to stick to than a conventional low fat calorie restricted diet.
2. Improved cognition and mental clarity. This is thought to be due to the brain’s use of ketones instead if glucose for fuel.
3. Reduced cravings for unhealthy foods. The taste buds change over time and cravings for starchy foods diminish.
4. Improvements and reversal of prediabetes and diabetes. Again very low carbohydrate diets have been shown to improve insulin resistance. The more insulin resistant a person is the more beneficial it is to restrict the intake of simple carbohydrates.
5. Increased energy and improved athletic performance. Ordinarily the body’s supply of stored carbohydrates (glycogen) only lasts for a couple of hours of intense exercise. After a few weeks of a ketogenic diet, the body learns to use its much more plentiful fat for fuel leading to longer endurance without constantly having to re-fuel. Even the thinnest person has thousands of calories of energy stored in body fat.
6. A ketogenic diet can be a helpful adjuvant for the treatment of epilepsy and possibly other neurologic disorders. While first used for children with epilepsy, the diet is now being used in some adults to reduce the amount of medication required to decrease the number of seizures. Use of the diet is also now being studied to treat other neurological disorders as well as for the prevention of Alzheimer’s in persons with a strong family history of the disease.
Detractors of the ketogenic diet point to possible health risks:
1. Eating so much fat is bound to lead to high cholesterol and heart disease. There is much debate about whether consuming dietary fats increases the risk of cardiovascular disease. What we do know is that all fats are not created equal. Most experts agree that fats such as those found in processed convenience foods (trans fats) are artificially produced from hydrogenated vegetable oils are not good for anyone. On the other hand, naturally occuring monounsaturated fats like those in avocados, nuts and olives as well as the omega 3’s found in salmon and sardines are quite healthy and have been shown to actually decrease the risk of heart disease. The controversy lies with saturated fats from animal sources like meat, poultry, eggs and dairy products. You can find studies that support the deleterious effects of animal fats as well as many others that fail to show any link between the consumption of animal fats and heart disease. The good news is that there are enough good healthy fats available that you can achieve the benefits of a ketogenic diet without eating animal fats at all. It is even possible to be vegetarian and/or vegan and still adhere to a ketogenic diet. The diet can be personalized to taste preferences and genetic profiles.
2. The body, especially the brain needs carbohydrates to function normally. This is a medical myth. The brain is perfectly capable using ketones to fuel its daily function once a person becomes fat adapted.
3. The diet causes too many side effects. In the first few weeks on a ketogenic diet, some people can experience lethargy, dizziness, leg cramps, bad breath, constipation and decreased physical performance. We established in an earlier blog that simple carbohydrates can be addictive. The so-called “keto flu” that some experience when starting a low carbohydrate eating plan is in part due to withdrawing from dependency on carbohydrates. The dizziness and leg cramps are usually related to the electrolyte loss from the increased urination in the early stages and respond to magnesium and salt replacement. All of these symptoms go away as the body adjusts to the lower carbohydrate intake.
4. The diet is “dangerous.” There are some individuals who should not be on a ketogenic diet without medical supervision. This would include diabetics, hypertensive patients on medication, patients on medication for mood disorders and those with severely abnormal lipid profiles. Such supervision is necessary because the diet causes shifts in body chemistry which might affect medication dosages and side effects. Supervision is also needed with pregnant and lactating mothers and for children whose protein needs may not be met by the standard ketogenic diet.
Those of us who have switched to a low carbohydrate eating plan for health reasons and have reaped the benefits see it as a long term lifestyle and not a quick fix. The bottom line to successful weight loss and maintenance is finding an eating plan that you can adhere to over the long haul. The question for you to ask yourself before embarking on the severe carbohydrate restriction of the ketogenic diet is whether this is something you can live with indefinitely. Otherwise, keto becomes just like any other fad diet with initial success followed by rapid weight regain caused by returning to the eating patterns that caused you to gain weight in the first place.
““Dear friend, I hope all is well with you and that you are as healthy in body as you are strong in spirit.”
3 John 1:2 NLT