Adolescence is a critical period of growth and development, so good nutrition is essential. The body demands more calories and nutrients during early adolescence than at any other time of life. Calories are the measurement used to express the energy delivered by food. On average, boys require about 2,800 calories per day; and girls, 2,200 calories per day. If they are active in sports, their requirements are even higher.
Nutrients and Energy
The nutrients protein, carbohydrates, and fats in food serve as the body’s energy sources. Each gram of protein and carbohydrate supplies four calories, or units of energy, whereas fat contributes more than twice as much: nine calories per gram.
Protein is an important nutrient needed for the growth and repair of cells. 50% percent of body weight is made up of protein. Protein can also be used for energy, especially if not enough carbohydrate foods are eaten. Protein needs are increased during times of cell growth and repair such as during childhood and adolescence.
Protein can come from animal or plant foods such as:
- Meat, chicken, fish
- Nuts and seeds
- Dried beans and lentils
- Dairy products such as milk, yogurt and cheese
Too Much Protein
Some people use protein supplements in an effort to build muscle. The best way to build muscle is to do exercise that uses muscle strength. Although muscle is made of protein, the preferred fuel for working muscles is carbohydrate.
It can be dangerous and harmful to adolescents, children and adults to follow diets high in protein or protein shakes and low in other nutrients. It can damage the kidneys and create a serious impact on their health. It is important that diet is well balanced and provides all nutrients essential for good health.
Carbohydrate is an important nutrient found in many foods. Carbohydrate is an important source of energy for the body. They are divided into complex and simple carbohydrates. Many complex carbohydrate-containing foods are high in dietary fiber and are healthy food choices. Complex carbohydrate-containing foods provide the body with energy throughout the day.
The rate at which carbohydrate-containing foods are digested varies greatly. Complex carbohydrate-containing foods are digested slowly and therefore provide a longer-lasting release of energy with a low glycaemic index (GI). It is often labeled on the food that we buy in the supermarket.
Simplex carbohydrates such as sweets, cakes, candies, chocolate, cupcakes, desserts etc provide high surge of blood sugar, fast and short release of energy with high GI index and their consumption leads to obesity and diabetes.
Low GI foods include wholegrain bread, pasta, oats, apples, banana, apricots and oranges, yogurt and milk, dried beans and lentils.
High GI foods include white bread, processed cereals, short-grain rice, potato, most cracker biscuits, watermelon.
Complex carbohydrate foods like breads and cereals are also fuel to the probiotic (healthy and beneficial) bacteria in our gut and which are essential for a healthy digestive tract. For good health, eat a variety of low GI, high fibre complex carbohydrate-containing foods each day.
Fresh, canned or dried fruits
Rice (preferably brown), bread (wholemeal), quinoa (also rich in protein), noodles and pasta (preferably brown/whole grain varieties)
- Low-fat milk and yogurt
- Whole grain breakfast cereals
- Legumes such as beans, chickpeas and lentils
- Starchy vegetables such as potato, sweet potato, carrots, corn
Fat is an essential part of our diet and is important for good health. There are different types of fats, with some fats being healthier than others. It is important to eat healthy fats in moderation as part of a balanced diet.
Unsaturated fats are healthy fats and are an important part of a healthy diet. These fats help reduce the risk of heart disease and lower cholesterol levels.
- Omega-3 fats which are found in oily fish such as salmon, sardines and anchovies, walnuts, canola oil, soy, chia seeds, flaxseeds
- Omega-6 fats which are found in safflower and soybean oil, some nuts, including brazil nuts.
- Found in olive and canola oil, avocados and some nuts, such as cashews and almonds.
Saturated fats are unhealthy fats, which may increase the risk of heart disease and high cholesterol levels. These fats are solid at room temperature and are found in:
- Dairy foods – such as butter, cream, ice-cream
- Meat – such as fatty cuts of beef, pork and lamb, processed meats like salami, and chicken skin
Some plant-derived products:
- Palm oil
- Coconut oil
- Cooking margarine
Saturated fats are also commonly found in many processed food::
- Fatty snack foods
- Deep-fried take away foods e.g. french fries, chicken nuggets, spring rolls, battered/crumbed fish
- Packaged cakes and biscuits
- Pastries and pies.
Vitamins are important building blocks in our diet. They are vitally important for function of different organs (vitamin A for eyes and vision), enzymes (vitamin B) and neuronal cells (vitamin B12 and folic acid), production of blood cells (iron, vitamin B12 and folic acid), wound healing (vitamin C), bones and teeth (calcium and vitamin D), for production of blood clotting factors (vitamin K) etc.
Diet for children growing adolescents is very important to be rich in vitamins and minerals. Vitamins are divided into oil-soluble vitamins (A, D, E, K) and the rest are water-soluble vitamins.
Best sources of vitamins
- Vitamin A: Dairy products, eggs, liver, fish, fortified cereals, darkly colored fruits, and leafy vegetables
- B1 (Thiamin): Whole grains, pork, beans, seafood
- B2 (Riboflavin): Milk, whole grains, dairy, beef, lamb, eggs, green leafy vegetables
- B3 (Niacin): Meat, fish, wholemeal breads and cereals, beans, peas, nuts
- B6 (Pyridoxine): Fish, poultry, lean meat, whole grains, potatoes
- B9 (Folate): Dried beans, green leafy vegetables, oranges, beans, poultry, fortified cereals, nuts
- B12 (Cobalamin): Fish, red meat, poultry, dairy products, eggs
- Pantothenic acid: Sunflower seeds, mushrooms, peanuts, yeast, yogurt
- Biotin: Peanut butter, hard-boiled eggs, wheat germ
- Vitamin C: Berries, kiwi, bell peppers, tomatoes, melons, citrus fruits, oranges
- Vitamin D: Egg yolk, fatty fish, and milk. Also made by the skin when exposed to sunlight
- Vitamin E: Vegetable oils, nuts, dark green vegetables, avocados, and whole grains
- Calcium: Dairy products (milk, yogurt, cheese, etc.), calcium-fortified juice, or soy milk
- Iron: Red meat, pork, fish, chicken, beans, soy foods, green veggies, and raisins
- Magnesium: Whole grains, whole-grain breads, nuts and seeds, potatoes, milk, and bananas
- Phosphorus: Dairy products, meat, and fish
- Potassium: Banana, dry fruits, beans, broccoli, potatoes (with skins), citrus fruits, peas, and other legumes
- Zinc: Red meat, chicken, seafood, soy foods, dairy products, whole grains, nuts
- Sodium: Usually used as a food additive or kitchen salt. Many processed food contain high amount of salt (NaCl). It's recommended that we eat less than 2,300 mg of sodium a day because it will lead to high blood pressure and water retention and headache.
Adequate intake of fluids during the adolescent years is important because it supports many body functions. Fluid requirements depend on size, age, and level of physical activity. Male adolescents should get 2.4 to 3.3 liters of water per day and female adolescents need at least 2.1 to 2.3 liters per day.
Water and other fluids keep tissues moist, regulates body temperature, lubricates joints, prevents constipation, supports kidneys and liver function and make nutrients available to the body. Dehydration can occur if an adolescent doesn't get enough fluids throughout the day and may result in kidney problems, developing kidney stones, skin conditions, including acne, allergy and asthma, fatigue, headaches, weight gain, and diabetes.
Not all fluids are suitable for hydration. Water is the best way to keep hydration. Many foods are high in water content and contribute to an overall fluid intake, including melons, citrus fruits, grapes, strawberries, carrots, lettuce, tomatoes, celery, and squash. Some sports drinks are good water alternatives for athletes, particularly ones who play hard for long periods of time.
Sodas and other soft drinks which contain caffeine, sugar, and other coloring artificial ingredients are not hydrating and create extra load of sugar which may lead to obesity and diabetes.