Elite Sports Performance Expo is the leading expo in the UK targeting elite athletes and coaches. It was held on 15-16 June at ExCel, London. At the show Rob Verkerk gave a well-received presentation that aimed to show endurance athletes how they could work with diet, supplements, nutrient/food timing and training schedules to help them become better fat burners, a state that makes an athlete – or indeed any individual – much less reliant on carbohydrate foods, drinks and energy gels while training or racing.

Physiologically, what becoming a better fat burner is all about is becoming more metabolically flexible. If we are over-reliant on carbohydrates we become less able to use burn fats as fuel and the body will always switch to carb burning rather than fat burning if carbs are supplied. Dr Verkerk’s presentation was entitled “Does Enhanced Metabolic Flexibility Equal Enhanced Endurance Performance?” and in this piece we’ve distilled some of the most pertinent take-homes and provided a summary graphic courtesy of our newest member of our team, Charlie Jones. We hope this information will benefit anyone interested in improving their health, fitness and endurance potential.

Key take-homes

  • A healthy, energy efficient body can switch ‘fuel type’ effortlessly from carbohydrate (carb) burning (i.e. glycolysis, which gives 2 or 36 molecules of ATP energy per molecule of glucose, depending on the presence of oxygen) to fat burning (i.e. beta oxidation of fatty acids, which for the fatty acid palmitate, yields 129 molecules of ATP energy per molecule)

  • Having the ability to switch from carb to fat burning as the primary energy-yielding system is referred to as keto-adaptation

  • The ability to switch from carb to fat burning is an evolutionary survival mechanism. It enabled us to survive periods of famine while searching and hunting for food, which were typically interspersed among cycles of rest feasting

  • Fat burning facilitates a more sustained performance over longer periods, and, gram for gram, yields over twice as much energy

  • ‘Carb junkies’ don’t give their bodies the chance to beta-oxidise fatty acids and become keto-adapted

  • If you are not able to adequately burn fats, you will typically run out of fuel after your glycogen (stored glucose in liver and muscle) is exhausted typically after around 60-90 minutes of moderate/high intensity endurance exercise. Those who are keto-adapted switch to fat burning at this point and so don’t have the same need to replenish with carbohydrate drinks, foods or gels

  • Walking and cycling are examples of good endurance activities that are reasonably easy to engage in for over 90 minutes, while avoiding undue over-exertion

  • Adequate and individualised recovery is important, being aided by the provision of protein and branched-chain amino acids (high in leucine especially) preferably within 30 minutes or so of completion of the activity. It is important for complex carbohydrates to be consumed as well, although this typically might be with the main meal,

  • After a few weeks of endurance exercise, there can also be a 50% increase in the volume of mitochondria, the energy producing powerhouses of the cells, which greatly benefits health, resilience, endurance and energy efficiency

How to improve your metabolic flexibility and become keto-adapted

Depending on the individual, some of the following recommendations may be more important than others, and different combinations may work better than others. The following list is therefore for guidance only.

  • Restrict energy (calories) intake by around 25% compared with in non-keto-adapted state
  • Engage in 18-hour (overnight) fasts 2-3 times a week
  • Engage in 12-hour (overnight) fasts 6 days/week
  • Consider alternate day fasting (<600 calories/day on fast days)
  • Consider the Fast Diet - 5:2 intermittent fasting
  • Don't consume food within a less than 5h interval from last meal
  • Avoid snacking
  • Exercise or train in a fasted state, generally before your first meal of the day after an overnight fast at least twice per week
  • Increase healthy fat intake to enable greater endurance
  • Alternate strength and endurance training on different days
  • Do HIIT and ensure adequate recovery, replenishing within half an hour of completion of exercise/training with high protein foods or shakes, including branched chain amino acids (BCAAs)
  • Eliminate refined and processed carbohydrates (and sugars) from the diet entirely
  • Bring your omega 3 (n-3):omega 6 (n-6) fat ratio as close to 1:1 as possible
  • Use ANH Food4health guidelines, obtaining 50-70% of energy from healthy fats, 15-25% of energy from quality protein, and the remainder from complex carbs. Maximise unprocessed foods and avoid refined carbs. Ensure you eat vegetables (and some fruit) from the 6 phytonutrient colour groups every day
  • Helpful supplements include high quality protein (non-dairy if any sensitivity to lactose), branched-chain amino acid (BCAA) supplements, resveratrol, curcumin, Coenzyme Q10, green tea and moderate to high dose vitamins, especially B1 (thiamin), B2 (riboflavin), B3 (niacin), B5 (pantothenate), B6 (pyridoxine), B12 (methylcobalamin) and methylfolate.
  • Use technology such as a body composition scale, a physical activity monitor (e.g. Suunto Ambit3) and a Ketonix meter to monitor visceral/adipose fat/muscle composition, physical activity and nutritional ketosis
  • Genetic testing through an appropriately trained functional medicine practitioner or personal trainer enables a more individualised and tailored programme to be developed.

Download A4 poster