Jessie the Dietitian: The Ketogenic Diet

Sep 4 / CATEGORY: Nutrition

Undoubtedly, you have heard about the ketogenic diet, or “keto.” Keto is frequently billed as a euphoric diet that allows all the fat one wants to eat while also losing all the fat. Well known in the neuro-medicine community as a treatment for intractable epilepsy since the 1920s, its popularity has shot up recently after a few celebrities experienced weight loss on the diet. Instagram currently has 10 million+ tags for #keto. Take a deeper dive with me to separate fact from fiction and pros versus cons of this hot topic!

The Basics

In the simplest of terms the keto diet is a very low- or no-carbohydrate eating plan that forces the body into a state of ketosis, an altered metabolic state that uses ketone bodies instead of glucose for energy. In general, the keto diet is composed of foods:

  • High in fat: 75% or more of total calories
  • Adequate in protein: 15% of total calories, about 1 gram per kilogram of body weight
  • Low in carbohydrates: 5% of total calories, usually less than 20 grams/day of ‘net carbs’

Ketogenic Diet Patterns

With keto’s growing popularity, many eating patterns have evolved from the original therapeutic diet of the 1900s. The most restrictive types are the classic ketogenic and the medium chain triglyceride (“MCT”) supplemented ketogenic diet, and slightly less restricted Modified Atkins Diet (“MAD”).

To maintain very high fat intake, keto dieters must incorporate many sources of fat into their diet; most fat is long chain triglycerides found in meat, fish, dairy products, eggs, oil, and organ meats. On the MCT keto diet, MCT oil is incorporated into the diet as a supplement or through foods including palm kernel oil and coconut oil. The MAD approach continues to restrict carbs but liberalizes protein intake, somewhat increasing palatability of and adherence to the diet.

Due to the highly restrictive nature of the diet eliminating most fruits, many vegetables and most grains, adults who choose to follow the keto diet will likely need dietary supplements including but not limited to a multivitamin, mineral and trace element, calcium, magnesium, folate, and vitamin D.  Some dieters choose to “cycle” off the diet 1-2 days per week after several weeks or months in ketosis, which may help to maintain adherence and reduce health risk factors.

Side Effects


  • Weight loss: The diet has shown good response to short-term, fast weight loss. Initially, a significant amount of water is lost as water-intensive glycogen stores are reduced, which is followed by loss of fat mass; if the diet is not closely followed and calculated, lean muscle mass will also be broken down for energy needs. Overall keto dieters report increased satiety and reduced hunger levels.
  • Neurological conditions: The diet continues to be a viable option for epilepsy and early research supports its potential use in malignant brain tumors, Parkinson’s disease, Alzheimer’s disease, and glaucoma.


  • Weight: The diet currently has no evidence to suggest long-term sustained weight loss. It is expected that this diet will fall into the category of similar restrictive diets that result in >95% of dieters regaining all the weight initially lost, and 75% gaining more than what was lost.
  • Keto flu: At onset, dieters can expect four to ten days of the “keto flu” due to electrolyte shifts causing dehydration and reduction in energy supply to the brain as it adapts metabolically. People report lethargy, irritability, headache, depressed mood, brain ‘fog’, constipation or diarrhea, muscle cramps, and bad breath initially; many of these symptoms resolve however GI symptoms and bad breath may persist.
  • Vitamin, mineral, and trace element deficiencies: Supplementation is essential.
  • Quality of diet: There is concern for overall long-term health consequences when dieters rely on artificial or convenience “keto” foods and snacks.  Furthermore many keto dieters choose high saturated fat diets including large quantities of butter and low-quality meats, increasing concerns for heart health.  The financial cost of a quality diet is typically higher.
  • Time & Mental health: The keto diet requires significant planning, meal preparation, and support system.  Due to the diet’s restrictive nature many dieters report social isolation (inability to dine with others), as well as preoccupation and obsession with food leading to disordered eating behaviors.


Expect to see more ketogenic foods, supplements, marketing/sales, social media posts, apps, and cookbooks. Research is catching up with this fad and a few long-term quality studies (>2 years) have been completed. It is an exciting time for research exploring how diet influences short-term and long-term health.


Thinking about ‘going keto’ or embarking on a similar diet change? Ask yourself, “Is this a plan that I can easily follow for the rest of my life and continue to find it enjoyable? Does it inherently provide all of the nutrients needed to thrive?  Will it help me maintain or improve my overall health? ” If your answers are mostly no or questionable, there’s a good chance that it is not in your best interest to pursue it at this time. Consider a one-on-one nutrition consultation with me to help you work through your nutrition lifestyle changes and goals.

-Jessie Furman, MS, RDN, LD/N, Coordinator of Nutrition