Carbs for weight loss and energy
There are two types of carbohydrates: simple and complex. Simple carbohydrates are found in foods such as sugar and milk, while complex carbohydrates are found in the fibres and starches of plant foods like wholegrains, vegetables and legumes. When you eat any kind of carbohydrate, your body extracts a fuel called glucose (blood sugar) and when you exercise, your muscles burn this stored glucose. Because complex carbohydrates are usually lower in fat and higher in nutritional value than simple carbs, they’re a better choice for everyone, including walkers like you. Complex carbs also offer healthy amounts of fibre, a substance that encourages weight loss because it’s bulky and therefore fills you up quickly, so you’ll eat less.
Power-Eating Tip: Go beyond starches. Slightly more than half of your total daily kilojoules - 55 to 60 per cent - should come from carbohydrates. Of that, only 40 per cent should be complex carbohydrates such as potatoes, whole grain breads and pastas, and fruits. The other 60 per cent of carbohydrate kilojoules can come from a variety of sources, including dairy. “Many athletes fail to realise that carbohydrates also occur in vegetables and dairy products, and thus they consume more starches than they need to,” explains sports nutritionist Kristine Clark.
Fat for endurance and immunity
Fat is an essential nutrient for good health, vitamin absorption, brain function, and energy. “Just as many athletes overconsume carbohydrates, they under consume fats,” says Clark. In fact, research shows that fat may increase your endurance and boost your immune system. When researchers had female soccer players eat 75g of peanuts (or 1,880 kilojoules from fat) every day for a week, the women ran nearly 1.5km further than when they ate their usual fare. When an extra 1,880kJ of carbs were substituted, there was no change. Another team of researchers studied trained runners and found that those who limited fat in their diet to about 17 per cent compromised their immune system. When the level of fat was raised to 32 to 41 per cent, performance improved without any jeopardy to immunity.
Power-Eating Tip: Don’t cut out too much fat. A super-low-fat diet is not recommended for those who work out, says nutritionist Dr Jaya Venkatraman. Instead, women should maintain a low- to medium-fat diet with 25 per cent of their kilojoules coming from fat, mostly in the form of monounsaturated and polyunsaturated fats. If you’re eating a typical 8,000kJ (2,000cal) a-day diet, you should be consuming up to 56 g of fat, which is about 11 teaspoons, from all food sources, preferably in the form of olive or canola oil, with very little of it in the form of butter.
Protein for muscle strength
“Protein builds and repairs body tissue, which might be damaged during exercise,” says exercise scientist and nutritionist Jackie Berning. Eating too much protein, however, strains your kidneys as they get it out of your body. Excess protein may also interfere with calcium absorption and make it more difficult to get the recommended 55 to 60 per cent of your kilojoules from carbs.
Power-Eating Tip: Avoid protein overload. Regular walkers need just 1.5 g of protein per kilo of body weight each day. For a 60kg woman, that’s 95 g of protein: the amount found in 1 cup of yogurt plus 2 cups of soybeans, or a veggie burger and 125g of chicken.
Calcium for bone strength
While weight-bearing exercise is important for strong bones, it’s only going to build the bones that you are using the most, explains exercise scientist Priscilla Clarkson. So if you’re a walker, your leg bones will be stronger. But your arms and back need protection too. That’s where calcium comes in. Athletic or not, most women don’t get enough calcium. When nutritionist Connie Georgiou questioned 104 female exercisers about certain foods, nearly one-third rated macaroni and cheese as unhealthy, and more than one-fifth said that light milk was bad for them. “They’re overestimating the amount of fat in dairy products and underestimating their calcium needs,” says Georgiou. Calcium-poor diets can lead to stress fractures and osteoporosis and may also be a cause of muscle cramps, since calcium plays an essential role in muscle contraction.
Power-Eating Tip: Have dairy at every meal, aiming for about 1,000 mg of calcium per day if you’re 50 years old or younger, or 1,200 mg if you’re older.
Water for performance
Women average 4.7 cups of water-based liquids a day, but you need a minimum of 13 if you exercise frequently, more if it’s hot outside or if your workout is strenuous. The extra fluid replaces what you sweat out and removes the body heat that you generate during exercise. According to exercise physiologist Mindy Millard-Stafford one of the major causes of fatigue during prolonged exercise may be due to dehydration.
Power-Eating Tip: Don’t wait until you’re thirsty to sip. Exercising blunts your thirst receptors, so make sure you drink before, during, and after exercise - whether you feel thirsty or not. A good rule of thumb is to take in 200-250ml of fluid every 20 minutes while exercising. To be safe, keep drinking even after your thirst is quenched. The simplest way to know whether you’re getting enough fluids is to check your urine. If you’re urinating about every two hours, and it’s light coloured or clear, you’re fine. If it’s dark or has a strong smell, you need more liquid. (Or try a drink bottle with measurements to track your intake)
Vitamins and Minerals for energy
Studies show that female athletes typically consume less than the recommended levels of zinc, B-complex vitamins, and iron, which can lead to fatigue. And women who are limiting their food intake in an effort to lose weight are even more likely to be deficient in some key nutrients.
Power-Eating Tip: It’s wise to take a daily multivitamin/mineral supplement and a 500 mg calcium supplement.
Here are a few more nutrients that deserve some special attention:
B vitamins: Even sporadic exercise increases your need for B vitamins, which your body needs to repair muscle and keep you energised. Good food sources for B vitamins include chicken breast, watermelon, banana, tomato juice, spinach, broccoli, and rice.
Iron: Iron is essential to the production of red blood cells and plays a vital role in transporting and helping the body use oxygen. Never take iron supplements unless under the direction of your doctor. Iron can be found in lean red meats, poultry, eggs, legumes, baked potatoes, soybeans, and clams.
Zinc: Even slightly reduced levels of zinc can make you feel sluggish. Oysters, lean ground beef, sirloin steak, turkey thighs and drumsticks, and lentil soup are all good food sources of zinc.