Food provides nutrients to keep your body healthy and running smoothly. But poor nutritional choices will reduce your power output during sessions, reduce your ability to recover from and adapt to your sessions, and impair your health. As previously discussed, there is more than one way to achieve a healthy eating pattern. This is because you might have dietary restrictions. But, no matter whether your restrictions are enforced or by choice, the human body has basic needs that must be met.
A healthy eating pattern: includes a variety of nutrient-dense whole foods
while limiting the intake of sugar, saturated fat, trans-fats, salt (sodium), and alcohol.
You can achieve this by eating: vegetables of all colours, fruits, grains, oils, protein foods, dairy or soy, and drinking fluid.
Doing so will provide you with carbohydrates, fats, proteins, vitamins, minerals, and water - everything the growing, recovering, and adapting body needs.
The precise number of calories you need to eat is tricky to dial in, but to maintain optimal health while training: your daily caloric intake must be sufficient in relation to your daily training load to maintain an adequate “energy availability” that allows your body to maintain normal physiological functions.
But, remember: being light does not equal being fast - always consider your power to weight ratio.
Throughout my posts on nutrition, I always aim to keep things generic to help you learn about healthy eating rather than to stress over number targets. But, a reference guide can sometimes be useful.
The tables below are derived from the dietary reference intake (DRI) guidelines, which vary between countries (click here for the various Food-based dietary guidelines within the United Nations, click here for the WHO nutrition pages, and click here for the EU DRV pages). Trying to precisely fit your diet to meet these values is a futile task; which is why I always say,
“Don’t stress over your nutrition! Simply aim to have fun with nutrition and enjoy your food journey. All is not lost if things get eff dup from time to time. Just aim to eat well on as many days as possible.”
IMPORTANT
DRI guidelines (dietary reference intake) are called the nutrient reference value (NRV) guidelines in some countries. DRI or NRV is the umbrella term that contains the framework of the following:
→ RDA (or RDI) is the recommended daily allowance (or intake), which is the amount that will meet the known nutritional needs of 97.5% of healthy people. RDAs are derived from population based studies and are 2 standard deviations above the average daily requirement to ensure people obtain sufficient quantities. RDA values were determined in population-wide studies, not just in athletes and physical activity levels of the subjects were not taken into account, but this does not mean that RDA do not apply to athletes.
→ EAR is the estimated average requirement of a nutrient that is estimated to meet the nutritional requirement of 50% of the healthy population. EAR values help assess the probability that the specific intake amount is inadequate for an individual and are used to calculate RDAs.
→ AI is the adequate intake value of a nutrient. This is assigned when there is no known EAR and, therefore, RDA cannot be calculated. AI implies low prevalence of inadequate nuteitnintakes and is based on observed or experimentally-determined estimates of nutrient intake for a group of healthy people. An individual consuming a level of a nutrient at or above the AI has a low probability of nutrient inadequacy.
→ UL is the upper tolerable limit at which nutrient intake of this amount is likely to pose no risk to health. The UL value estimates the percentage of the population at risk of adverse effects of excessive nutrients intake. If a person’s intake is higher than the UL value, the individual is at a greater risk of adverse effects.
Reference values vary between countries and may change as new evidence comes to light.
The reference values below are for non-pregnant adults aged 19 to 50.
Some values change in pregnancy, which generally requires an additional 300 kcal/d and an increased need for protein, folic acid, and iron. So, consult your doctor if you are planning to become pregnant or are pregnant.
Some values, like calcium, vitamin D, and vitamin B12, increase after menopause and in older men.
For athletes, the relative amount of carbohydrate and fat needed to optimise recovery and performance may change from day to day in relation to the intensity and/or duration of their sessions.
kcal = kilocalories; and KJ = kilojoules
1 kcal = 4.184 KJ
g = grams; mg = milligrams; μg = micrograms
1 g = 1000 mg = 1,000,000 μg
FFM = fat-free mass = body weight − body mass mass
When energy availability is 30-40 kcal / kg FFM / day for men and 30-45 kcal / kg FFM / day for women may be tolerated for short periods but is considered subclinical low energy availability.
When energy availability is less than 30 kcal / kg FFM / day, this represents clinical low energy availability, which leads to loss of normal bodily functions and loss of recovery from and adaptation to exercise.
Remember, all values are for non-pregnant adults aged 19 to 50.
Energy availability (EA) is the remaining kcal of energy left when subtracting daily exercise energy expenditure (EEE) from daily energy intake (EI).
EA = (EI − EEE) ÷ fat-free mass in kg
For example:
A male athlete weighing 75 kg with 8% body fat has a fat-free mass of 69 kg (0.92 ✕ 75). Today he ate a total of 3000 kcals (EI) and expended 1000 kcals (EEE) during his sessions so his energy availability was 29 kcal/kgFFM (2000 ÷ 69), which is too low because it did not leave enough energy available to maintain normal bodily function. For him to have achieved 40 kcal/kgFFM of energy availability today while maintaining the same training load, he should have eaten 3760 kcals (i.e. [40 ✕ 69] − 1000), an extra 760 kcals.
* This means “available” carbohydrate that is absorbed, i.e. not including fiber.
# One drink is a small (125 mL) glass of wine or small (300 mL / half-pint) glass of 5% beer.
Remember, all values are for non-pregnant adults aged 19 to 50.
Note: there are approx 4 kcals in 1 g of available carbohydrate, 9 kcals in 1 g of fat, 4 kcals in 1 g of protein, and 7 kcals in 1 g of alcohol.
For further reading, see the 2016 Nutrition and Athletic Performance joint position statement published by the Academy of Nutrition and Dietetics (AND), Dietitians of Canada (DC), and American College of Sports Medicine (ACSM) in Med Sci Sports Exerc.
Remember, all values are for non-pregnant adults aged 19 to 50.
Fat-soluble vitamins can be stored in the body, water-soluble vitamins cannot. Therefore, water-soluble vitamins must be consumed daily. Many of the water-soluble vitamins - Thiamin (B1), Riboflavin (B2), Niacin (B3), Pantothenic acid (B5), Folate, and Vitamin C - cannot be synthesised in the human body and are called “essential” vitamins.
Vitamin D (specifically vitamin D3 or cholecalciferol) can be synthesised from cholesterol in the skin when exposed to UVB radiation in sunlight. Since sunbathing is not safe, dude to cancer risk, vitamin D intake is recommended.
# Meat is the only natural food source of Vitamin B12 (cobalamin). B12 is found in fermented soy, some seaweeds and other algae but is otherwise not found in plant foods. Vegetarians, including vegans, should eat B12-fortified foods or supplement with B12.
* For some vitamins and minerals, insufficient evidence exists to set an RDA so an adequate intake (AI) value is assigned based on expert consensus.
DRI/NRV values for micronutrients are likely appropriate for athletes because of the large “safety net” the recommended intake values, which are greater than the minimum amount needed to survive and high enough to account for low bioavailability. That said, adjustment may be needed for some athletes with very high energy expenditure or with diets with poor nutrient bioavailability (e.g. vegetarians).
Remember, all values are for non-pregnant adults aged 19 to 50.
* For some vitamins and minerals, insufficient evidence exists to set an RDA so an adequate intake (AI) value is assigned based on expert consensus.
** Percent absorption represents the portion of the ingested amount that is absorbed into the blood through the intestine; meaning that the percentage not absorbed is excreted in your poop.
DRI/NRV values for micronutrients are likely appropriate for athletes because of the large “safety net” the recommended intake values, which are greater than the minimum amount needed to survive and high enough to account for low bioavailability. That said, adjustment may be needed for some athletes with very high energy expenditure or with diets with poor nutrient bioavailability (e.g. vegetarians).
The tables above are a supplement to, not a replacement for, the nutrition articles I write. The tables are not to be used for self-diagnosis. As an athlete, maintaining sufficient energy availability for all bodily functions is critical for maintaining your health during training and competition. Always, remember that:
Normal bodily functions should be maintained even when training hard. Losing normal bodily functions must never be worn as a badge of honour to indicate that you are training hard. This includes loss of reproductive functions like regular menses or erectile function. It is not healthy or “normal” to lose such functions when training.
If you are concerned about your body weight, your reproductive function, and/or your nutrition,
consult your doctor right away,
arrange a consultation with a registered nutritionist/dietician,
and
inform your coach.
Disclaimer: I occasionally mention brands and products but it is important to know that I am not sponsored by or receiving advertisement royalties from anyone. I have conducted biomedical research for which I have received research money from publicly-funded national research councils and medical charities, and also from private companies, including Novo Nordisk Foundation, AstraZeneca, Amylin, the A.P. Møller Foundation, and the Augustinus Foundation. I have also consulted for Boost Treadmills and Gu Energy on their grant applications. These companies had no control over the research design, data analysis, or publication outcomes of my work. Any recommendations I make are, and always will be, based on my own views and opinions shaped by the evidence available. The information I provide is not medical advice. Before making any changes to your habits of daily living based on any information I provide, always ensure it is safe for you to do so and consult your doctor if you are unsure.
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About the author:
I am Thomas Solomon and I'm passionate about relaying scientific information to the masses and helping folks meet their fitness and performance goals. I hold a BSc in Biochemistry and a PhD in Exercise Science and am an ACSM-certified Exercise Physiologist and Personal Trainer, a VDOT-certified Distance running coach, and a Registered Nutritionist. Since 2002, I have conducted biomedical research in exercise and nutrition and have taught and led university courses in biochemistry, molecular medicine, and exercise physiology. My work is published in over 80 peer-reviewed medical journal publications and I have delivered more than 50 conference presentations & invited talks at universities and medical societies. I have coached and provided training plans for truck-loads of athletes and regular folk, have competed at a high level in running, cycling, and obstacle course racing, and continue to run, lift, and climb as often as possible. To stay on top of scientific developments, I participate in journal clubs and peer-review papers for medical journals, and I invest every Friday in reading what new delights have spawned onto PubMed. In my spare time, I hunt for phenomenal mountain views to capture through the lens, boulder problems to solve, and for new craft beers to drink with the goal of sending my gustatory system into a hullabaloo.
includes a variety of nutrient-dense whole foods 
IMPORTANT 
DRI guidelines (dietary reference intake) are called the nutrient reference value (NRV) guidelines in some countries. DRI or NRV is the umbrella term that contains the framework of the following: 
consult your doctor right away, 
arrange a consultation with a registered nutritionist/dietician, 
inform your coach. 
Buy me a beer.
