Being vegetarian doesn't mean you have to compromise on performance. Anecdotal evidence suggests that a vegetarian diet for endurance athletes is by no means detrimental. However, an athlete who consumes a poorly planned vegetarian diet may be at risk of nutritional deficiencies as well as poor physical performance.
General healthy-eating guidelines as well as specialist requirements for athletes apply to meat-eaters and vegetarians. You daily aim should be to base your meals and snacks on starchy carbohydrates; you should also include two portions of protein-rich food, at least five of fruit and vegetables, and three of calcium-rich (dairy or alternative) foods.
Nutrients lacking in the vegetarian diet will depend on the foods excluded: protein, omega-3 fats, iron and zinc may be deficient if meat, poultry, fish and eggs are excluded. Add calcium to that list if milk and dairy foods are excluded. To ensure you're including enough of these vital nutrients, try the following:
Protein and calcium
Include dairy products and/or eggs in your diet and you're unlikely to be protein deficient, but since triathletes require slightly more protein than less active people, it's worth taking extra care that your diet contains protein.
Research shows that vegetarian athletes can meet their protein requirements if they regularly include the following foods in their diet: soya products such as tofu, tempeh, mince and beans; Quorn and Quorn products; pulses, including lentils, peas and beans; nuts, nut butters and seeds; and cereals and grains such as bread, pasta and rice.
If you're going for the diary-free option, try soya milk, yoghurt, cheese, calcium-fortified rice milk and oat milk.
Low iron stores can ultimately result in anaemia, but even before that, lack of iron can affect performance and lead to excessive tiredness. Female vegetarian endurance athletes appear to be particularly vulnerable to low iron stores and anaemia. They need to pay attention to their intake and effective absorption of iron.
In general, plants contain less iron than animal foods and only two to 20 per cent of iron from plants is absorbed by the body, compared with 15 to 35 per cent from meat. Worse still, there are various compounds in everyday foods that affect iron absorption.
These compounds - phytates (found in bran, wholegrain cereals, tofu and oats), polyphenols (found in tea, coffee, spinach and herbs) and tannins (found in tea and coffee) - can hinder iron absorption, but eating vitamin C-rich foods along with foods containing iron will increase the amount of iron you absorb.
Maximise your iron intake by avoiding tea with meals, having a glass of orange juice with a bowl of fortified breakfast cereal, and consuming iron-containing vegetables such as peas, kale, broccoli and pak choi, which have lower levels of phytates.
Try to include iron-rich snacks in your diet. Dried fruit (especially apricots and figs), seeds (pumpkin, sesame and sunflower), fortified cereal bars, wholemeal toast and blackstrap molasses are good options.
Recent evidence suggests these fats may play a role in promoting fat burning but they are also essential for good health. Omega-3 fats are found in oily fish such as fresh tuna, salmon and sardines, but plants contain a much less potent type of omega-3 fats that need to be converted by the body into the more active form.
Our bodies are not very efficient at doing this, which means that if you're not eating the recommended two portions of oily fish a week, you may struggle with your intake. Including the following foods will help: pumpkin seeds; rapeseed oil (vegetable oils are often pure rapeseed oil); flaxseeds and flaxseed oil; walnuts and walnut oil; soya products such as yoghurt, milk and tofu; and omega-3 fortified foods such as spreads, yoghurts and eggs.
Your immune system needs zinc to function effectively. As with iron, vegetarian sources of zinc may be poorly absorbed because of the phytate concentrations in plant foods; in addition, plant foods don't contain as much zinc as animal foods.
Regularly include these plant sources of zinc in your diet: peas, beans and lentils; hard cheeses; wholegrain products such as bread, breakfast cereal, pasta and rice; fortified cereal bars; nuts and seeds; and