The Science Behind the Ketogenic Diet
The ketogenic diet is a very low-carb, moderate-protein, and high-fat diet which puts the body into a state known as ketosis: a metabolic shift in which the body is burning fats rather than carbohydrates as its primary source of fuel. This is a pretty simple definition, but in order to fully understand how the ketogenic diet works and its benefits, it is important to have a grasp on exactly how the body uses energy in the first place:
Normally, when carbohydrates are consumed in the diet, they are converted to glucoseand insulin.
- Glucoseis the simplest form of sugar, meaning that it is easy for your body to convert and use as energy. This is why glucose is the body’s preferred source of energy.
- Insulin is a hormone that is produced by the pancreas to process the glucose in your blood steam by transporting it around the body to where it is needed. When energy levels are sufficient, insulin will convert glucose to adipose tissue (fat) for later use.
With the average high-carbohydrate diet, glucose is the main energy source because there is an abundance of it. However, the body can only store a limited amount of glucose—only enough to last for a couple of days. Therefore, if we forgo eating carbohydrates for a few days, our body relies on other means for energy through a biochemical process known as ketogenesis.
In ketogenesis, the liver begins to break down fat as a usable energy source instead of carbohydrates. Ketones or ketone bodies are produced as an alternative energy source to glucose. Once ketogenesis kicks in and ketone levels are elevated, the body is in ketosis.
How to Enter Ketosis
There are a few ways to body can enter ketosis. One is by fasting: when you stop eating altogether for an extended period of time, the body will ramp up fat burning for fuel and decrease its use of glucose. Another way to get into ketosis is by eating less than 20-50 grams of carbohydrates per day (it will vary per individual). Therefore, people on a ketogenic diet get only about 5% of their calories from carbohydrates.
Steps to enter ketosis:
- Cut down on carbs (less than 5% of calorie intake)
- Increase your consumption of healthy fats (up to 80% of calorie intake)
- Without glucose being used for energy, your body is now forces to burn fat and produce ketones instead
- Once the blood levels of Ketones rise to a certain point, you officially enter into ketosis
- This state results in consistent, fairly quick weight loss until your body reaches a health and stable weight
Benefits of a Ketogenic Diet
Unlike many fad-diets that come and go, the ketogenic diet has been practiced for more than nine decades (since the 1920s) and is based upon a solid understanding of physiology and nutrition science. This diet works well for so many people because it targets several key, underlying causes of weight gain—including hormonal imbalances, elevated insulin and high blood sugar levels. A ketogenic diet has even shown to offer therapeutic benefits for several brain disorders.
- Weight loss: A diet high in fat and low in carbohydrates, such as the ketogenic diet, helps to diminish hunger and boost weight loss through hormonal effects. When we eat foods that supply us with carbohydrates, we release insulin. But with lower levels of insulin, the body is less likely to store extra energy in the form of fat and instead able to use existing fat stores for energy. A diet high in healthy fats and protein is also much more filling, which can help curb appetite and reduce the overconsumption of empty calories, such as sweets and junk food.
- Cholesterol and Blood Pressure: A ketogenic diet has shown to improve triglyceride and cholesterol levels most associated with arterial buildup. More specifically low-carb, high-fat diets show a dramatic increase in high density lipoprotein (HDL) and decrease low density lipoprotein (LDL) particle counts as compared to traditional low-fat diets. Many studies also show better improvement in blood pressure. High blood pressure issues are often associated with excess weight, which is a bonus because the ketogenic diet tends to lead to weight loss as well.
- Controls Blood Sugar: A ketogenic diet also helps with lowering blood sugar levels by controlling the release of insulin. This can help reverse problems such as insulin resistance or pre-diabetes. Studies have shown ketogenic diet to reduce HbA1c levels—a long term measure of blood glucose control (1). Therefore, because this diet works so well at reducing blood sugar levels, it also has the additional benefit of helping people with type 2 diabetes to reduce their dependence on diabetes medication, however, it is important to speak with your doctor prior to starting a ketogenic diet or adjusting any medications.
- Fights Neurological Disorders: Over the past century, ketogenic diets have been used to treat and even help reverse neurological disorders and cognitive impairments, including epilepsy. Research shows that cutting off glucose levels with a very low-carb diet makes your body produce ketones for fuel. This change can help to reverse neurological disorders and cognitive impairment. The brain is able to use this alternative source of energy instead of the cellular energy pathways that aren’t functioning normally in patients with brain disorders. In a study of children who suffer from epilepsy, over half had a greater than 50% reduction in seizures when eating a ketogenic diet, while 16% even became seizure free (2). The benefits of a ketogenic diet are now even being studied for other brain disorders, including Parkinson’s and Alzheimer’s disease (3).
So, what can I eat on a ketogenic diet?
A keto meal should contain high amounts of healthy fats, such as olive oil, coconut oil, grass-fed butter or ghee, palm oil, avocado, tree nuts, seeds, and fatty cuts of wild-caught fish, grass-fed beef or bison, and free range poultry. Fats are a critical part of every ketogenic diet because fat is what is providing energy for your body and preventing hunger, weakness, and fatigue. Keto meals also need a good amount of non-starchy vegetables, such as broccoli, leafy greens, asparagus, cucumber, zucchini, and other cruciferous vegetables.
The types of food you will want to avoid when eating a ketogenic diet include items like fruit, processed foods or drinks high in sugar, those made with any grains of white/wheat flour, conventional dairy products.
Rachel Scheer is a Certified Nutritionist who received her degree from Baylor University in Nutrition Science and Dietetics. Rachel has her own private nutrition and counseling practice located in McKinney, Texas. Rachel has helped clients with a wide range of nutritional needs enhance their athletic performance, improve their physical and mental health, and make positive lifelong eating and exercise behavior changes.
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