By Erin Kukura, MS, RD
UCSD Recreation Dietitian
What is the Keto Diet?
The ketogenic diet is a high fat, low carbohydrate diet, touted for health benefits such as short-term weight loss and improvements in cholesterol and lipid levels (1). It was originally designed for children who suffer from epilepsy as a possible alternative treatment to those who were not responsive to medications (2).
How does Keto work?
Our body’s primary energy source is glucose (broken down from carbohydrates we consume), which supplies our brain and cellular energy needs. Our brain alone requires a minimum of 120g of glucose per day, not to mention the energy demand on all of our organs and muscles that also utilize this energy to maintain basic human functions.
The idea of adhering to a ketogenic diet is to switch your body from utilizing glucose as the primary energy source to rely on breaking down stored fat and fat you consume, to supply energy for cells and ketones to be used by the brain. Our body uses this method when we deplete glucose and stored glycogen such as during periods of fasting or extreme exercising (typically only for the short-term).
In order to remain in this period of ketosis, one must maintain an extremely low carbohydrate intake otherwise your body will switch back to glucose metabolism and it will take a few days to convert back to ketosis. Additionally, your body can also break down protein instead of fat which is why only a moderate amount of protein is consumed in this style of eating.
What can you eat on a keto diet?
Because keto is minimal in carbohydrates, a variety of beneficial foods are extremely limited or altogether excluded including whole grains, legumes, beans, fruits and vegetables. This means most people on keto lack adequate amounts of fiber (important for bowel regulation, lowering cholesterol, and impacts the gut microbiome) and also limits beneficial nutrients such as antioxidants, vitamins, and minerals. Incorporating these kinds of foods into your diet has been linked to a lower risk of chronic diseases.
Keto is also incredibly high in fat (upwards of 70-80%), which can be extremely unpalatable. We also know that there are different kinds of fats that can have effects on inflammation and heart health (ie saturated versus unsaturated fats).
What the research says:
There are currently no long-term studies done on keto so we don’t know what this means for how this might impact our health long-term. Most studies that have shown benefits to weight loss have been only done in the short-term (a few weeks) and often without any control group.
The keto diet is extremely restrictive, eliminating the majority of an entire food group (carbohydrates) that is essential to our health and well-being.
Numerous data supports restrictive diets are not sustainable and results in weight rebound, disordered eating behaviors, depression and worsening self-esteem (4,5).
There is currently no long-term data to support health benefits of following this eating pattern at this time.
I understand it can be easy to get sucked into the allure of diets touted on social media and by our friends and co-workers. But I encourage you to think about what your experience has been like when you follow restrictive eating plans. How do these affect your energy, mood, thoughts about food and ultimately your eating behaviors? Typically, it worsens these and we are left with more guilt, frustration and chaotic eating habits all of which are not leading us on the path towards health and wellbeing.
Instead, it’s better to look overall at your eating patterns and health behaviors to find what areas you can adjust to make sustainable long-term changes that will result in better health outcomes rather than following restrictive, fad diets.
- Westman, E. C., Mavropoulos, J., Yancy, W. S., & Volek, J. S. A review of low-carbohydrate ketogenic diets. Curr Atheroscler Rep.November 2003. Pages 476-483.
- Wheless, J. W. History of the ketogenic diet. November 2008.
- Diet Review: Ketogenic Diet for Weight Loss. https://www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/ketogenic-diet/
- Mann, T. Medicare’s search for effective Obesity Treatments: Diets Are Not the Answer. Am. Psychologist 62, 3 (2007): 220-233.
- Tribole, Evelyn and Resch Elyse.Intuitive Eating. New York, New York. St Martin’s Griffin (2012).