You may have come across the term “keto” lately in conversation, or seen it on food packaging, recipes, and across social media. Pictures of fatty foods like bacon, cheese, and even butter in coffee. As with most topics in the spotlight, what you see may not be the whole truth.
Let’s talk about what ketosis really is and what the science is saying about the diet. But first let’s cover the basics. The ketogenic diet is unique from other styles of eating because of its very high fat, and very low carbohydrate intake.
Ketogenesis may seem like a new concept, but it is the natural process your body reverts to when it does not have enough glucose to use as energy. Your body will begin to break down fat and create ketones as an energy source. It’s kind of like your body’s built in backup generator!
Glucose is a form of sugar that is usually your body’s (especially your brain’s) main source of energy. When glucose is low, your body dips into your ketones that have been made from ketogenesis for energy. This alternative metabolic process your body switches to is known as ketosis. One job of your liver is to make ketones consistently anyway, but the amount will change based on one’s carbohydrate and protein intake. The rate of generating ketones slows when it is simply not needed. But with the keto diet, your body doesn’t get enough glucose to use it as its fuel. Instead, your body stays in a state of ketosis.
• Epilepsy: The ketogenic diet was first used clinically to treat seizures. It has been used to successfully reduce seizures for many years, with research to back up the benefits outweighing any cons.
• Weight loss: There are some great metabolic changes initially with this diet. In a published article titled Ketogenic Diet for Obesity, Paoli notes that the health parameters associated with carrying excess weight improve, such as insulin resistance, high blood pressure, and elevated cholesterol and triglycerides. It is true that fat oxidation does increase due to the body adapting to the higher dietary fat intake. However, fat oxidation and losing body fat are two different processes. When fat oxidation is higher it does not necessarily mean that there will be a reduction in body fat. Overall calorie intake and calorie burn will be the main determinant in fat loss.
• Type 2 diabetes: Carbohydrate restriction can have a direct impact on glucose concentrations, lowering them over time. It may be a straightforward way one
could get their diabetes under control. But one should consult a registered dietitian before utilizing this strategy, as a general healthful diet and carbohydrate control can produce the same results.
• Cancer: This is a growing area of research for the ketogenic diet. The Warburg effect has established that tumor cells can break down glucose much faster (specifically 200x faster) compared to typical cells. The theory is that by “starving” tumor cells of glucose, you can inhibit their growth and help prevent cancer.
Some negative side effects of a long-term ketogenic diet have been suggested in a review of the diet by Harvard’s school of public health, including increased risk of kidney stones and osteoporosis, and increased blood levels of uric acid (a risk factor for gout). And the biggest areas of concern below.
• Nutrient Deficiencies: Because whole food groups are excluded, nutrients typically found in foods like whole grains and fruit that are restricted from the diet can lead to deficiencies, especially if the diet is followed incorrectly or without proper guidance. It is vital to incorporate a wide variety of foods while eating such high amounts of fat. Each food group offers different essential nutrition. Focus on meats, seafood, vegetables, some legumes, and fruits to make sure you are getting fiber, B vitamins, and minerals such as iron, magnesium, and zinc. It would be best to consult with a registered dietitian to alleviate the possibility of any deficiencies that can affect you long term.
• Keto Flu: During the diet transition you may experience uncomfortable side effects from significantly cutting carbs, sometimes called the “Keto Flu”. Hunger, headaches, nausea, fatigue, irritability, constipation and brain “fog” may last days. Sleep and hydration will help, but it may not be a pleasant transition into the diet.
• Adherence: Point blank, following a very high-fat diet may be challenging to maintain for most. Keeping yourself satisfied with a limited variety of food and food groups and not being allowed to have some of the more pleasurable foods like fruit, rice dishes, pasta, or ice cream, may be challenging to maintain. This is very individual but adhering to a healthy diet is important. To truly gain long-term health benefits, one must have healthy habits in place year-round, not 30 days at a time.
• Gut Health: Using the restroom may be difficult since removing whole grains and fruit will greatly lower one’s fiber intake. Not great for gut health.
To sum things up
•Regarding fat loss, someone may try something extreme temporarily, and if it works, they can reap those physical benefits correlated with losing body fat. Once the diet is complete there may be a more complex transition or normal eating again. Or, if it is used for the long term, there have not been studies yet to see how this impacts our health.
• What we do know is that an overall nourishing, vitamin packed diet (or way of eating) should include high quality foods, variety, and the ability to adhere to the diet whether it is for fat loss, muscle gain, or general maintenance.
• The ketogenic diet is missing some vital food groups, and in turn, vital nutrients.
• It is best to consult with a registered dietitian and physician to ensure you are monitoring not just the scale, or how you feel, but what is going on in your body internally with the proper guidance.
• As with all nutrition recommendations, they are individual, in relation to a person’s health history, preferences, goals, activity level, as well as special health needs. It is the role of the registered dietitian nutritionist to guide clients toward a safe, health-optimizing lifestyle through personalized nutrition, and to stay up to date with the newest and most thorough research. What may work for one, may not for another. And what we know now, may also change in the future.
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Branco AF, Ferreira A, Simões RF, et al. Ketogenic diets: from cancer to mitochondrial diseases and beyond. Eur J Clin Invest. 2016;46(3):285-98. doi:10.1111/eci.12591.
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Johnston CS, Tjonn SL, Swan PD, White A, Hutchins H, Sears B. Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets1–3. Am J Clin Nutr. 2006;83(5):1055-61. https://www.ncbi.nlm.nih.gov/pubmed/16685046. Accessed September 29, 2016.
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Wheless JW. History of the ketogenic diet. Epilepsia. 2008;49(Suppl 8):3-5. doi:10.1111/j.1528-1167.2008.01821.x.