Physical activity is defined as any bodily movement, produced by skeletal muscles, that requires energy. The contribution of physical activity to good health and quality of life has been known for centuries. It is a health promotion priority interlinking with weight management and can have both a preventive and therapeutic effect across several diseases and conditions.
Optimum nutrition for sports performance:
macronutrients & micronutrients
A well-balanced and varied diet will usually be enough to meet the
nutritional needs of most physically active people. The
tips below give advice on how to eat and drink well while being active, to help
us feel energetic, perform well and recover faster.
A normal diet containing 1,800-2,400 calories per day (25-35
kcal/kg bodyweight) typically provides enough energy for exercise (where one
exercise session burns 200-400 calories). We
get our energy and nutrients mainly from the three macronutrients:
carbohydrates, protein and fat. The following advice is based on the
energy and nutrient requirements of adults involved in general
fitness programmes (e.g., exercising 30-40 minutes per day, 3 times per week),
although carbohydrate loading for athletes is briefly discussed. Exact
needs will vary based on individual factors such as age, gender, height and
activity level.
Macronutrients
Carbohydrates
Carbohydrates are an important source of energy. A normal diet,
where approximately half (45-55%) of the daily calories come from
carbohydrates, provides enough for most moderately active people. For example,
a person weighing 70 kg needs about 210-350 g carbohydrates per day, preferably
coming from complex carbohydrates which contain fibre
including whole grains, fruits and vegetables.
The following examples each give 30 g carbohydrate:
·
Bowl of oats (45 g)
·
2 slices of bread
·
4 crispbreads
·
½ serving of pasta or rice (~40 g uncooked)
·
1 large banana (~145 g)
·
3 servings (3 x 80 g) of high-carb vegetables like lentils, peas,
sweetcorn, carrots
·
1 large potato (~150 g)
·
Fruit smoothie (250 ml)
·
(or Sports drinks (500 ml): see fluid section for more details)
Very active people, who perform high intensity exercise regularly (e.g. 2-3 hours intense exercise per day, 5-6 times per week), will need to consume extra energy and increase carbohydrate intake to 55-65% of total daily calories. This can come from carbohydrate rich foods that are low in fibre such as white bread and non-wholegrain cereal products or fruit juices and smoothies as well as sportsdrinks. The exact amount needed increases with the amount and the intensity of exercise.
When is
‘carbohydrate loading’ useful?
‘Carbohydrate loading’ is useful for athletes taking part in
events lasting more than 90 mins to maximise energy stores before their event.
This involves eating 10-12 g of carbohydrate per kg body weight, per day, for
1.5-2 days before the event, while also resting from training. For
a person weighing 70 kg, this translates to 700–840 g carbohydrate per day
(contributing 2,800-3,350 kcal). Thus, the intake of carbohydrate should be
doubled or tripled for one or two days before the high intensity exercise.
“Periodised
carbohydrate intake” involves varying carbohydrate intake in relation to
exercise sessions (e.g. training in a fasted state, eating high carbohydrate
for competitions). This can improve performance in endurance sports such as 10
km races. A
qualified sports nutritionist/dietitian can advise on a periodised plan to suit
your needs including what types of food to eat and when.
Is eating
low-carbohydrate beneficial for exercise?
There have been claims in the media that a low-carbohydrate
high-fat diet (75–80% fat) can improve performance in athletes, by increasing
the amount of fat that muscles burn and reducing how much they rely
on carbohydrate. However, research shows eating a low-carbohydrate high-fat
diet does not benefit performance. This
is because a high fat diet decreases efficiency of the muscle during exercise.
Protein
Dietary protein is important to repair muscles after exercise and to make new muscle. Those who follow a general fitness program have the same protein needs as the general population, which is about 0.8 g of protein per 1 kg of body weight per day. If training intensely, we need extra protein (1.4-2 g/kg body weight per day, or around 100-140 g protein per day for a person weighing 70 kg) Be careful not to exceed the recommendations, since an excessive protein intake can have negative effects on several organs, such as the kidneys.
The following examples each give 10 g of protein.
·
2 small eggs
·
50 g fish or chicken
·
120 g tofu
·
200 g yoghurt
·
250 ml cows’ milk / 300 ml soy milk
·
40 g cheese
·
60 g nuts or seeds
·
150 g kidney beans
Meat,
fish, eggs, and milk are high quality protein sources, as they
contain high levels of essential amino acids, which are needed for protein
synthesis in muscles. Most
research on optimal protein sources for active people has focused on milk
proteins (casein and whey). Milk proteins are better digested and absorbed, and
support muscle build up better than soy protein. Vegans
can meet their daily needs by eating a variety of protein-rich plant foods such
as legumes (e.g. beans, peas, chickpeas, lentils), grains, nuts and seeds.
Fat
Active people need a moderate amount of fat (about 30% of daily calories), which can easily be achieved
by including oily fish (like salmon), vegetable oils or spreads, nuts, seeds
and avocado in the diet.
