A lot of people freak out about protein when following a ketogenic diet. There is an idea that eating a high, or even moderate protein diet, will result in large amounts of glucose creation from amino acids in protein (gluconeogenesis). However, this idea is unfounded and there are significant benefits from increasing your protein intake.
What is ketosis?
Ketogenic diets are those that elicit the state of ‘ketosis’. This state of ketosis refers to the production of ketone bodies, derived from fats (and some amino acids) for use as an alternative fuel in times of fasting or drastic carbohydrate restriction.
When glycogen reserves become insufficient to supply glucose to the Central Nervous System (CNS), an alternative fuel source is needed. Ketones, especially beta-hydroxybutyrate (BOHB) provide this fuel, which can be used by the brain and CNS, and by most tissue (including muscle tissue) throughout the body.
What are ketogenic diets?
The ketogenic diet itself is a form of LCHF diet that is very low in carbohydrate, low-to-high in protein and moderate-to-high in fat. It is often termed a ‘very low carbohydrate ketogenic diet’ (VLCKD). Keto diets are characterised by the expression of ketone bodies in the blood, breath, and urine. This expression of ketones is a ‘functional’ nutritional ketosis (NK) and this nutritional ketosis is usually defined by levels of ketones (specifically BOHB) in the blood of > 0.5 mmol/L.
Gluco = sugar, neo = new, genesis = creation.
So, gluconeogenesis is the creation of glucose within the body. This is an essential process that allows the body to produce glucose from the glycerol backbone of triglycerides (fats) and most importantly, from amino acids (the building blocks of protein).
Isn’t gluconeogenesis ‘bad’ for ketosis?
Not really… and the reasons are two-fold.
- Gluconeogenesis is DEMAND, not supply-driven.
This means that the body will use the glycerol liberated from fatty acids during the breakdown of fat for fuel, to create glucose which is required in the body to fuel certain cells that can’t use fat or ketones (like red blood cells). If there is an additional requirement, the body will convert amino acids to glucose as required.
- The old-style keto diets had to be extremely low in protein to allow very high blood ketone levels to reduce the frequency and severity of seizures in children with epilepsy.
To most effectively reduce seizures, a high blood ketone level of around 2-3 mmol/L + is preferred. (1) However, nutritional ketosis for most athletes and people in the mainstream doesn’t need to be sustained at this high level and ketosis is now defined as anything above 0.5 mmol/L of BOHB. (2-6) Protein has an insulin response, and this does reduce ketosis (albeit slightly) and so, to create larger amounts of ketones in these early diets, protein was restricted. With lower demand for ketones in modern keto-diets not for epilepsy, protein can be increased without affecting the ability to get into and sustain ketosis.
So, high protein intake can result in higher insulin levels and excess amino acids from protein can be converted to glucose, but this has only a small effect on ketogenesis. Nowadays, we can also enhance ketone body production with MCT oil (allowing ketosis with higher intakes of both protein and carbohydrate) and directly ‘boost’ ketone levels with exogenous ketone supplements, when required.
Higher-protein, low-carb diets
High-protein, low-carbohydrate diets have actually been studied quite extensively for weight-loss and improving body composition. They typically perform better than high-carbohydrate calorie-restricted diets (no surprise there) and have been used to enhance weight-loss with greater loss of body-fat, and reduced loss of muscle along with improved blood markers of health. (7-11)
Increased protein on a low-carb diet can be extremely beneficial, resulting in improved satiety (feelings of satisfaction and fullness from eating) and thermogenesis (calorie burning) when compared to equivalent amounts of either carbohydrates or fat. (12, 13) There is a higher thermic effect of feeding (TEF) (using more calories) from protein ingestion as compared to either carbohydrate or fat. (14-16) Higher protein keto-diets have been shown to increase weight loss and provide more satiety than high protein, moderate carb diets. (17)
There are significant benefits from increasing protein intake irrespective of diet, including:
- Improved bone health (18)
- In older adults, high-protein nutritional supplements are associated with lower hospital admissions and fewer health complications. (19)
- Older adults retain more lean mass and lose more fat mass during weight loss when consuming higher protein diets. (20, 21)
- Increased dietary protein has a small, beneficial effect on blood pressure, reduces triglycerides (one of the most important markers of poor cardiovascular and metabolic health), and reduces body fat stores. (22, 23)
For those dieting, or even those who are just habitual under-eaters, an increased protein intake of up to 2.5 g per kilogram of body weight is likely to help offset muscle loss, and thus improve body composition (muscle to fat ratio) resulting in a leaner you. (24)
This level of protein is around 3 x higher than the recommended daily allowance of 0.8g per kg body weight! Not only that but for ‘weekend warriors’ training for sports, or at the gym, protein taken after training might reduce soreness. (25) And in healthy adults, over the long term, protein is likely to increase lean muscle and help to improve strength and power. (26)
How to Apply This
Increasing your protein intake won’t excessively inhibit ketosis (although there might be a small reduction in ketones) not reduce your ability to lose fat or gain muscle, in contrast, there will be likely benefits to body-composition and overall health from an optimised protein intake. So, set protein at an appropriate level for your goals rather than out of fear of gluconeogenesis.
Protein recommendations (per kg of body weight per day)
- For athletic and general populations and to offset age-related muscle loss: ~ 1.4 g – 2.2 g
- When dieting: ~ 2.5 g
- When gaining muscle: ~ 2 – 2.5 g +
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