What is the Keto Diet?
The Ketogenic Diet is a very low carbohydrate (<20g / day), high fat, normal protein intake diet. The diet induces the human body to produce energy in a different pathway than it normally does. Rather than using sugar (glucose) as the main source of energy, the Ketogenic Diet tricks our bodies into thinking it is in a fasting state and shifts our metabolism into a new mode of production. It creates ketone bodies – rather than glucose- as the primary source for fuel. These ketone bodies are made in the liver and eliminated through our bodies by the kidneys (detected in our urine) and our lungs (detected in our breath). This blog post will explore the different types of food emphasized on the Ketogenic diet, how the Ketogenic Diet affects health, weight loss, diabetes, cardiovascular risk factors, and its overall safety.
Ketogenic Diet Foods:
Here is a simplified diagram from the Ketodiet Blog:
Ketogenic Effects on Health
In the short term, the Ketogenic Diet is a tool to improve risk factors for obesity, high cholesterol, and cardiovascular disease. Evidence supports effective weight loss while on the Ketogenic Diet when compared to low-fat diets, however, the underlying mechanism is debated and not well supported by the literature. In addition, studies on the long term effects of weight loss are lacking.
One study in 2013 using 89 subjects, looked at long term weight loss and improvements in health risk factors when two brief episodes of the Ketogenic Diet were alternated with longer periods of the Mediterranean diet.
Longer term weight loss were noticed as well as successful reductions in cholesterol, LDL (“bad cholesterol”), triglycerides, and sugar levels over the span of 1 year. The overall compliance using this alternating pattern of the Ketogenic Diet and the Mediterranean diet was very high.
Hypotheses of how the Ketogenic Diet may affect weight loss:
- Appetite reduction from the ketone bodies
- Lowered production of ghrelin (the “I’m hungry” signal) in the bloodstream
- Reduction in storage of new fat and an increase in the breakdown of stored fat
- Improved efficiency in metabolizing consumed fats
- Increased energy costs to create new glucose (sugar) and produce ketone bodies
Ketogenic Effects on Diabetes
In the short term, a diet with very low carbohydrate intake (like the Ketogenic Diet) has beneficial effects on:
- Sugar levels
- Hemoglobin A1c levels (3 month history of blood sugar in the body)
- Cholesterol levels
- Reduction in use of insulin and diabetic medications
When the body shifts to making ketone bodies, it is described as “ketosis.” The mechanism of ketosis in this dietary context is different than the disease process known as Diabetic Ketoacidosis (DKA).
Simply stated, DKA is when the level of glucose in the body becomes overwhelming with the potential to make us very sick- requiring hospitalization for correction. For those interested, below is a table comparing sugar levels (glucose) in the bloodstream at baseline, while on the Ketogenic Diet, and when in the disease state of DKA.
Ketogenic Effects on Cardiovascular Disease
A meta-analysis evaluating long-term management of obesity compared 13 randomized controlled studies on very low carbohydrate ketogenic diets (< 50g / day) and conventional low-fat diets (< 30% of energy from fat / day). In the overall analysis, the ketogenic diet individuals showed greater weight loss and a decrease in diastolic blood pressure (bottom number on a blood pressure reading).
Ketogenic individuals had an increase in HDL and LDL cholesterol. The clarification with LDL cholesterol is that the ketogenic diet has been reported to increase the larger-sized LDL particles (versus smaller, denser LDL particles which have a higher risk of causing plaque build-up in our arteries).
These findings point toward reduced risk factors for cardiovascular disease in Ketogenic participants – at least in participants who were studied over 1 year and when compared to conventional low-fat dieters.
Is the Ketogenic Diet Safe?
Yes. The Ketogenic diet is safe as long as you do not have problems with your kidneys, diabetes, blood pressure, or obesity with metabolic syndrome. As always, it is best to be evaluated first by your Primary Care Physician and to discuss if the Ketogenic Diet is right for you prior to starting.
In terms of the risk for Diabetic Ketoacidosis- for those who do not have problems with regulating glucose and insulin in their diet- being on a very low carbohydrate ketogenic diet naturally maintains ketone levels below 8 mmol/L. Therefore, the risk of diabetic ketoacidosis is low.
Take Away Points
Very low carbohydrate diets like the Ketogenic Diet are effective at weight loss and improvements in diabetes and cardiovascular risk factors when utilized in the short-term (3 weeks to a 6-12 months), and when transitioned into the Mediterranean Diet. The Ketogenic Diet helps control hunger and hormone levels and improves fat metabolism. Scientific studies are lacking on long-term health outcomes and are needed for better understand of benefits > 1 year.
Are there any small changes you could make to better align with the Keto diet?
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- Bueno, N.B.; de Melo, I.S.; de Oliveira, S.L.; 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, 110, 1178–1187.
- Int J Environ Res Public Health. 2014 Feb 19;11(2):2092-107. doi: 10.3390/ijerph110202092.
- Paoli A, Bianco A, Grimaldi KA, Lodi A, Bosco G. Long term successful weight loss with a combination biphasic ketogenic Mediterranean diet and Mediterranean diet maintenance protocol. Nutrients. 2013 Dec 18;5(12):5205-17. doi: 10.3390/nu5125205. PubMed PMID: 24352095; PubMed Central PMCID: PMC3875914.
- Paoli, A.; Grimaldi, K.; Toniolo, L.; Canato, M.; Bianco, A.; Fratter, A. Nutrition and acne: Therapeutic potential of ketogenic diets. Skin Pharmacol. Physiol. 2012, 25, 111–117.