• Sarah Greenfield, RD

The Basics of a Ketogenic Diet

Fat is truly having its moment in the spotlight. A macronutrient that has been demonized is now making a comeback and rightfully so. You may be familiar with the ketogenic diet or maybe have heard of bulletproof coffee and maybe you are confused about it all. Well fear not, today I will give you the science, impacts on health, the benefits and if the ketogenic diet is right for you!

What is the Ketogenic Diet?

The ketogenic diet is an extremely low-carb, high fat diet. The breakdown: typically it’s about 70% of total calories coming from fat and about 25g of carbs or less per day. That’s the equivalent of a medium sized banana which provides about 27 grams of carbs for the entire day! The goal of the ketogenic diet is to switch your metabolism from using glucose (sugar) as fuel to using fat (fatty acids) for fuel.

Below is a diagram of two different pathways our bodies can use to produce energy.

The Science

The ketogenic diet was originally developed in the 1920’s when researchers found that fasting had anti-seizure effects on patients they were studying. When the body switched fuel sources, from glucose (carbohydrates) to ketones (fat), it stabilized brain function.

This diet has come into favor in the athletic world as well because fat is a much more sustainable, longer lasting way to burn energy. Fat adapted endurance athletes need to consume less fuel, have improved VO2 max output and are more efficient fat burners; improving their endurance.

Impacting Health

Switching metabolism from using sugar to using fat is a natural process but there will be a period of adjustment as hormones and electrolytes rebalance. This is often referred to as the “keto flu.” Historically we have gone long periods of time without eating and our bodies are still able to provide us fuel and energy. So while this may feel uncomfortable initially, once the body switches over it is an effective way to utilize stored energy.

  • Cancer

  • Lower carbs diet can have anti-tumor effects on the body. Since many tumors feed on sugar, cutting off their food source can help shrink them.

  • Brain Health

  • Research is being done on the positive impact a keto diet and calorie restriction can have on parkinson's disease and alzheimer's

  • Switching children's diets to keto who are on the autism spectrum, has shown an improvement in concentration, social skills and autistic behaviors

  • Diabetes

  • Higher fat diets can help balance and stabilize blood sugars and are also linked to weight loss, an important factor in managing diabetes

Adding in Supplements

Following a balanced diet is most important, but sometimes you need a little extra boost!

  • Fiber

  • Constipation may occur if you are not eating enough fiber. Make sure to include nuts, seeds, berries and low carb veggies. You can also add in a fiber supplement to reach your daily fiber intake goals.

  • MCT Oil

  • Getting 70% of your calories from fat can be challenging, taking a high quality MCT oil can help you reach your goals. MCT oil is wonderful because it is absorbed easily and can is readily available for energy.

  • Protein Powder

  • Find a low-carb protein powder (I like Garden of Life Sports Formula). Smoothies are an easy way to hit your macronutrient needs and stay in ketosis.

  • Exogenous Ketone Salts

  • Since carbohydrates help hold onto water in the body, electrolyte balance can be thrown off when decreasing carbohydrate intake. Including bone broth is a great source of salt, and a good source of magnesium and potassium is important. Ketone salts give the body everything it needs to stay balanced.

Should you try it?

The ketogenic diet is a challenging diet to adhere to not only because you feel physically sick for the first couple weeks, but you are also significantly changing the way you eat. If you are concerned about disease conditions and how this diet would impact your overall health, talk to your healthcare provider before making any dietary changes.

I usually suggest trying a more paleo based diet to start. This will help decrease your overall carbohydrate intake without the “flu-like” symptoms. I really like the Whole30 approach as a way to ease into a paleo diet. It focuses on whole, real, clean foods and has made many people feel better overall.

In some cases I will suggest the ketogenic diet to people who are active that are looking to lose that last bit of fat. It can help you move through a weight-loss plateau. Whenever you limit a large macronutrient category, it is best to do this under the guidance of a professional to assure you aren’t putting yourself at risk for any nutrient deficiencies. If you are interested in learning more or have any questions, you can schedule a free call with me, HERE!

Final Thoughts

As with anything nutritionally related, the results can vary from person to person. There are some who thrive on a very low-carb diet while others just can’t get to a place where they feel healthy. Genetics, environment, stress levels, nutrient levels and sleep all play a huge role in how this dietary change can impact your body. No matter how much we learn, research and use technology, the only person who knows what feels best for your body is YOU. Listen to your body, see how it reacts when you try new things, be honest with what makes you feel better.


Sarah Greenfield RD, CSSD


16550 Riverside Drive


Studio City CA 91602 



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