Nutritional Ketosis

Peter Attia MD describes his own n=1 experiment in nutritional ketosis.  In ‘An Advantaged Metabolic State: Human Performance, Resilience & Health’, Peter describes how he overcame his state of metabolic syndrome by using a low-carbohydrate diet.  Peter describes his objectives in the talk as:

1. Share my health and performance journey
2. Provide you with an understanding of how energy balance research is carried out
3. Pique your curiosity about nutritional ketosis
4. Leave you with a framework for thinking about your own potential nutritional transformation.

I found Peter’s talk to be frank, personal ,witty and inspiring.  Having been following a low-carb paleo diet for the last 4 weeks it was also very useful and supportive.  I’ve eaten paleo for 2 years but this is my first serious foray into low-carb eating.

Having explained his objectives Peter said that this talk is not an in depth look at the science of ketogenic diets, or even to persuade you that this would be the best dietary approach for yourself.

Metabolic Syndrome

At age 35 Peter, a marathon swimmer, was the first person to double-cross the Maui channel.  Despite his impressive level of fitness Peter was overweight with 20% fat and metabolic syndrome.  A sign of insulin resistance, metabolic syndrome is diagnosed once you have 3 of the following 5 signs:

1. High blood glucose (sugar)
2. High blood pressure
3. Central obesity (fat around the abdomen)
4. Low HDL-cholesterol
5. High triglycerides.

Metabolic syndrome puts you at risk of cancer, Alzheimer’s disease, obesity, diabetes, stroke and coronary heart disease.  With a family history of heart disease, Peter set about his journey of experimentation by slowly reducing first sugar, then high glycaemic carbs until he was into nutritional ketsosis.

Keto-adaptation

Nutritional ketosis, or keto-adaptation, is the process by which the body adapts to a low-carbohydrate diet by relying on lipid-based fuel sources, especially fatty acids for muscles and ketones for the central nervous system.  According to Volek & Phinny (see link to their book at bottom of this post):

‘At the most basic level keto-adaptation involves an increase in the body’s production and utilization of ketones.  However, this is a complex and co-coordinated sequence of highly orchestrated events requiring adaptations in the type of fuel used by most cells in the body.  Ketone production occurs mainly in the liver in response to a combination of increased delivery of fatty acids and depletion of hepatic glycogen reserves.  The ketones produced in the liver are then transported by the circulation to other cells in the body including muscle and brain. In skeletal muscle, the first few days of keto-adaptation result in increased use of both ketones plus fatty acids from a variety of sources (adipose or intra-muscular triglycerides, or from circulating very low density lipoprotein particles).  Once the process of keto-adaptation is complete (which takes from a few weeks to a month), muscle at both rest and during exercise comes to rely heavily on fatty acids.  This adaptation of muscle away from ketone use spares hepatic ketone production for use by other tissues, especially the brain.’

‘This is a key point.  Practically speaking, the brain can burn only glucose or ketones.  On a very low carbohydrate diet, the brain comes to rely on ketones as its primary fuel.  Although ketones are preferentially taken up by the brain, because of the large mass of skeletal muscle and the increase in blood flow to active muscles during exercise, this delayed shift of the muscles away from ketones and towards fatty acid use is vital to preserving fuel flow to the brain during exercise in the keto-adapted athlete.  In part, the time it takes the body to choreograph these changes in whole body fuel flow explain why keto-adaptation takes a couple of weeks rather than just a few hours or days’.

We can live healthily in a state of nutritional ketosis by eating:

• A moderate amount of protein.  This equates to a normal portion size of protein such as a chicken breast, salmon fillet or 2 – 3 egg omelet.
• Less than 50g per day of carbohydrate.  This would be from non-starchy vegetables and low-sugar fruit such as strawberries.
• High fat – concentrating on healthy saturated (e.g. coconut oil) and mono-saturated fats (e.g. olive oil) with a small amount of omega-3 and -6 polyunsaturated fats (e.g. salmon).

Using this approach Peter was able to lose weight and improve all the metrics available in modern medicine – higher HDL-cholesterol, lower triglycerides, leaner without significant muscle loss and more insulin sensitive.  Peter had overcome his metabolic syndrome.

Peter details his personal experimentation of a keto-adapted state on such measures as VO2, VCOE, RQ, fuel partitioning using gas measurements, metabolic chambers and so on.

An Advantaged Metabolic State

His personal findings corroborate the findings of science researchers in recent years that low carbohydrate diets in keto-adapted athletes:

• Are anti-inflammatory, producing less oxidative stress during exercise and more rapid recovery between exercise sessions
• Greater reliance on body fat both at rest & during exercise with less dependence on muscle glycogen & less need to reload with carbohydrate during and after exercise.  Peter will, for example,  ride his bike for 3 hours before consuming some low-glycaemic carbs like salted nuts.  Body fat stores vastly exceed maximum stores of carbohydrates so there is less ‘bonking’ or ‘hitting the wall’.
• Accelerates the body’s use of saturated fats for fuel, allowing a high intake of total fats (including saturates) without risk
• Suitable for both endurance and strength/power sports.
• Improve insulin sensitivity.
• Spare protein from oxidation preserving lean tissue
• Better preservation of cognitive function during endurance exercise.
• Better tolerance of training at altitude.
• Not having to load with carbs before and during exercise leads to less gastro-intestinal distress.  Peter recommends branched chain amino acids to prevent muscle catabolism during extended endurance work.
• Avoiding wide excursions in blood sugar and insulin by burning predominately fatty acids and ketones can lessen the ’stress’ response to exercise.