Recently, I have had many clients ask me about the efficacy of the Ketogenic Diet for weight loss and optimal health. Ketogenic diets are characterized by being high fat, very low carbohydrate and low to moderate in protein. Recently, it has become more of a fad diet for weight loss, though its original purpose was for treatment in individuals with epileptic seizures. Before I discuss the pros and cons, I’ll explain what this diet really is.
In essence, a ketogenic diet mimics starvation, allowing the body to go into a metabolic state called ketosis. Normally, the human body is used to using excess glucose stores as a primary fuel source. When we consume carbohydrates (bread, pasta, even fruit), these foods are broken down into glucose, which is then transported and used as energy or stored as glycogen in liver and muscle tissue.
On very very low carbohydrate diets (usually below 50g/day), the liver becomes the sole provider of glucose (fuel) for our body through the process called gluconeogenesis. This is important for maintaining brain function. (Did you realize that our brain uses approx. 20% of total energy expenditure? ) Due to the limited amounts of carbohydrates available for fuel, the body has to find another fuel source. With fat making up a bulk of the foods consumed on a Ketogenic diet, fat becomes the primary fuel source. The result of using fat for energy is the production of ketone bodies.
Ketone bodies are made in the liver as byproducts of body fat and/or dietary fat. Once produced, they enter the blood stream and become fuel sources for our brain and other organs. These ketones are specifically: β-hydroxybutryate (BHB), acetoacetate and acetone. The production of ketones helps prevent low blood sugar by this mechanism: when the ketones are used as a fuel source instead of glucose, blood glucose remains physiologically normal due to glucose derived from certain amino acids and the breakdown of fatty acids.
In a clinical setting, a dietitian helps monitor specific ratios of fat to carbohydrate and protein combined. The ratios are often 3:1 (fats/carbs+protein ) for infants, children and adolescents and 4:1 (fats/carbs+protein) for adults.
In layman’s terms, a ketogenic diet is approximately 75% fat, 20 % protein and 5% carbohydrate. The carbohydrate portion would be a small handful of low-carb veggies.
- Small amounts of protein (beef, turkey, chicken, fish, eggs, shellfish)
- Small amounts of low-carb veggies (leafy greens broccoli, cauliflower, Brussels sprouts, cabbage
- Asparagus, cucumber, celery, peppers, mushrooms, zucchini)
- Large amounts of avocado, oils, butter, cheese, nuts and nut butter, bacon, egg yolk, coconut milk and other coconut products)
- Cereals/ Grains
- Most dairy (except high-fat items like butter and certain cheeses)
- Beans and legumes
- Starchier vegetables (such as sweet potatoes, parsnips, beets, winter squash, even carrots)
- Most processed foods (which is a good thing)
Research shows that following a ketogenic diet can be beneficial for people with the following conditions:
- Traumatic brain injury
- Parkinson’s disease
- Alzheimer’s disease
- Other neurological conditions
There has also been some research to support benefits for:
- Overweight and obesity
- High blood sugar, metabolic syndrome, diabetes (both type 1 & type 2)
In the case of obesity, this study shows the benefits that the ketogenic diet had in overall weight as well as lipid levels and blood glucose levels. In addition to weight loss, at the end of the 24 week period, the subjects experienced a significant decrease in the level of triglycerides, total cholesterol, LDL (“bad”) cholesterol and glucose, and a significant increase in the level of HDL (“good”) cholesterol. These benefits exceeded those observed in obese individuals being studied on a low-fat diet. An important thing to consider is that any reduction in simple carbohydrates, which tend to make up a bulk of the Standard American Diet (S.A.D.) is going to result in weight loss. Simple carbohydrates/starches are more likely to spike blood sugar levels and result in inflammation. Replacing these food items with foods that have a minimal impact on blood sugar levels will naturally result in improved blood sugar and lipid levels. Basically, by reducing carbohydrate intake and increasing consuming lean proteins and healthy fats, you’re likely to see improvements without fully entering ketosis.
For epilepsy, countless research has shown that seizures often decline or disappear during periods of fasting . Following a Ketogenic diet provides the same benefits regarding production of ketones without having to fast. According to the epilepsy foundation, several studies have shown that over half of children who go on the diet have at least a 50% reduction in the number of their seizures. They further report that some children, usually 10-15%, even become seizure-free.
Though the exact reason that the ketogenic diet works so well to prevent seizures is not yet established, it is known that it closely mimics the “starvation” state without actually having to fast. It is hypothesized that increased levels of the ketone: blood β-hydroxybutryate decreases seizures. However, new evidence suggests that rather than the presence of the ketones, it might be the relatively short-chain fatty acids (nanoeic and decanoic acids) that are present when on a ketogenic diet crossing the blood-brain barrier, that actually inhibit seizures. Either way, the evidence showing the benefits is sound.
The diet has been used mostly in children with difficult-to-control, generalized epilepsies that tend to be resistant to other treatments such as those with the Lennox-Gastaut syndrome. Studies have found that in this group of individuals, the diet can be as successful as medications. Recent studies have shown that the diet may also be effective in those with partial seizures.
It is most commonly used in children ages 2-13, but can be used in adults as well. In children, it is important to note that they likely will not gain weight or grow much during the time the diet being followed. This is because many essential nutrients are not included (those coming from fruits, whole grains, beans/legumes, most dairy, etc). After that, however, growth is expected.
Symptom relief and a halting in disease symptom progression have been seen in those with ALS, Parkinson’s, TBI and Alzheimer’s following a ketogenic diet. This diet is very difficult and requires commitment to fully reap the benefits. It is highly recommended to only do this under the guidance of a registered dietitian.
Another form the Ketogenic Diet is the Whals Paleo Plus protocol developed by Dr. Terry Wahls. She follows this protocol herself to reverse Multiple Sclerosis (MS). Her method is far more nutrient-dense, to include a wide variety of vegetables. Again, her purposes are for a neurological disease, not for weight loss. You can read more about her research and protocol in her book The Wahls Protocol and on her website.
Long-term adherence to a ketogenic diet can have the following negative impacts on health
- Kidney stones
- High cholesterol levels in the blood
- Slowed growth or weight gain
- Bone fractures
- Gut dysbiosis (overgrowth of unhealthy bacteria resulting in IBS symptoms)
- Vitamin/mineral deficiencies
Some of these side effects can be reduced by being “smart” with food choices. This requires adequate fluid intake (min of ½ body weight in oz of water per day) to help prevent dehydration and kidney stones. Bone fractures can be a result of osteoporosis from poor calcium intake/malabsorption and low vitamin D intake. A diet high in fat and low in carbs also limits very nutrient-dense fruits and starchier vegetables. This doesn’t provide a balanced diet and for that reason, supplementation is necessary.
Chronically low intake of carbohydrates can have a negative impact on gut flora.
According to Paul Jaminet, PhD and author of The Perfect Health Diet, he explains that “a ketogenic diet is more likely to cause autoimmune disease than cure it, due to the depletion of the mucus layer of the intestine, which puts bacteria directly into contact with immune cells.” He further explains that “carbohydrates are necessary to maintain this protective mucus layer.” I want to point out that these are healthy carbohydrate sources such as sweet potatoes, whole grains, beans and legumes, starchy veggies and fruits—not pasta, cereal, etc.
If you have thyroid problems, the Ketogenic diet is not recommended, nor is a very low carbohydrate diet. According to Kris Kresser, MS, L.Ac, we need insulin in order to convert inactive T4 intro the active T3 hormone. Insulin levels tend to be very low when following a low carbohydrate diet. Moderate carbohydrate intake is generally recommended for those with thyroid issues. This doesn’t mean excessive consumption, but about 30-40% carbohydrate intake.
Other factors that might increase your carbohydrate needs include:
High activity level, especially with a focus on frequent, high-intensity based workouts
- Poor recovery from workouts
- Adrenal fatigue
- Amenorrhea (loss of period) or have irregular cycles (pre-menopause)
- During pregnancy and while breastfeeding
Females tend to be more sensitive to lower carbohydrate diets, as it can have negative impacts on hormone health and fertility. To read more, check out this article by Stephanie Greunke, RD.
If you have a neurological disorder, seek out the assistance of a Registered Dietitian to help guide you through the process. If you don’t have epilepsy or another neurological disorder, I would not recommend implementing a ketogenic diet. It provides more risks than benefits, due to the low nutrient diversity.
There has been other research to support the benefits of a lower carbohydrate diet on diabetes, PCOS and insulin resistance, but this doesn’t require fully adopting a Ketogenic Diet. Paleo (low to moderate carb or 20-40% total intake) tends to work just fine.