The Keto Diet: Is It Worth It?

The Ketogenic diet… I get a lot of questions about the keto diet so I figured I would dive into what it is, what it’s used for and if it’s actually beneficial. Firstly, I want to recognize that people who are asking and looking into the keto diet are typically wanting to make a positive change for their health so I commend them for that. I also appreciate when someone is looking for a second opinion from an RD instead of taking Dr. Google’s word for it. 🙂

Basically, when done correctly, the keto diet is a very low carb diet limited to about 20- 50 grams per day and a very high fat diet. This causes the body to go into ketosis, when the body uses fat as fuel instead of glucose. After restricting carbs to these low levels for 3- 4 days your body goes into what it thinks is a fasted state with little to no starches and begins to use fat as the primary source of energy. This transition causes a drop in the production of insulin and increase in the formation of ketones from acetyl-CoA, a reaction called ketogenesis. (1) The brain’s primary fuel source is glucose but when this is not an option ketones are produced to serve as an interim fuel source. This diet has been shown to help epilepsy patients due to hypothesized changes in neurotransmitter productions and ketone production (2) as well as insulin sensitivity and hemoglobin A1c, although research has been unable to pinpoint a direct cause and effect explanation of the latter. (1) 

Short term, the keto diet has been shown to successfully cause weight loss. Let’s look at the probable factors for this. 1) You are most likely in a calorie deficit while on the keto diet. While on the keto diet you eliminate entire food groups including no legumes (beans, lentils, chickpeas), fruits, starchy vegetables, and whole grains. You’re also advised not to eat any sugar or refined carbs which also creates a calorie deficit if people usually include these in their diet. So really, there is not anything magical necessarily about keto itself but the calorie deficit you are in that’s creating weight loss. 2) The keto diet has a dehydrating effect on the body which causes the body to lose more water. On a very low carbohydrate diet your body will no longer store as much glycogen (the storage form of glucose) and water in the muscle. The loss of water causes a drop in weight so initially when people see lbs come off this could very well just be water weight and not fat loss. Additionally, the drop in insulin caused from the keto diet causes the body to excrete more salt and water from the body which would also cause a reduction in water weight. (3)

As a Registered Dietitian, there are many concerns that come up if  I hear a client is on a keto diet for general health purposes. The first is the keto diet has been shown to raise the harmful cholesterol levels (LDL) correlated with heart disease. (4) This is most likely due to the increased consumption of saturated fats on this diet through a higher intake of meats (especially fatty varieties like red meat, bacon, etc.) and dairy products such as cheese and butter, as research has shown saturated fats have been shown to increase blood cholesterol levels. Another major area of concern with eliminating entire food groups such as fruits, legumes, starchy vegetables and whole grains is that you are at a much higher risk of nutrient deficiencies since these are high sources of vitamins, minerals, and fiber, essential to a well balanced diet.

Fiber is imperative for gut health, as this is the prebiotic food that feeds the healthy bugs in your gut and we are still learning so much about gut health and how important it is for our overall health and immune system. While limiting so many great sources of fiber it can be much harder to get in the recommended daily intake of fiber which is 25 grams for women and 38 grams for men. Most people struggle to get enough fiber already without these limitations. Without enough fiber, constipation also becomes an issue which leaves waste and toxins sitting in your system longer than it should be. Additionally, research has shown a wide variety of plants consisting of fruits, vegetables and whole grains to also help the diversity of your gut bacteria. If people start eliminating entire food groups such as whole grains or fruits this is limiting the potential for those beneficial bacteria species to colonize in the gut. 

Overall, strict diets such as keto diets may help with short term weight loss but the keto diet has not been studied for it’s effects or safety long-term and especially not proven to be sustainable long-term because of it’s strict limitations. Therefore, as soon as people stop the keto diet and resume eating like they did before, typically the weight comes back on. In addition to the many health concerns of nutrient deficiencies, elevated cholesterol, lack of fiber, decreased gut health, the keto diet can also lead to orthorexia, obsessive thoughts, disordered behaviors, or stress around food which is definitely not beneficial for overall health. 

For these reasons I do not recommend the keto diet diet for general health purposes or weight loss but would advocate for eating more plants and closer to a Mediterranean type diet. A plethora of research has shown the benefits of plant based and Mediterranean type diets for heart health and longevity. I understand it may not sound as sexy or exciting to tell your friends about starting your new “Mediterranean diet” or “increased plant intake diet” but trust me it’s more flexible, sustainable, and intuitive to follow for the long-term!

Looking for more specific guidance to help meet your personal health goals? I’d love to chat with you. You can schedule your free call here. 

​1. Abbasi J. Interest in the ketogenic diet grows for weight loss and type 2 diabetes. JAMA. 2018;319(3):215-217.​

2. Roehl, Kelly, and Sarika L. Sewak. “Practice Paper of the Academy of Nutrition and Dietetics: Classic and Modified Ketogenic Diets for Treatment of Epilepsy.” Journal of the Academy of Nutrition and Dietetics, vol. 117, no. 8, 2017, pp. 1279–1292., doi:10.1016/j.jand.2017.06.006.

​3. Kulczycki, Stephanie. Keto Diet: A Dietitian’s Perspective – Chicago Academy of Nutrition & Dietetics | CAND (eatrightchicago.org)​

4. Bueno NB, de Melo IS, de Oliveira SL, da Rocha Ataide T. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. Br J Nutr. 2013 Oct;110(7):1178-87. doi: 10.1017/S0007114513000548. Epub 2013 May 7. PMID: 23651522.