What is nutrition?
Generally speaking, nutrition refers to the process by which living organisms take in and utilize food materials. The same word is also used to describe food itself and the science of dietary requirements for proper health and development.
Why is nutrition important for weight training?
Nutritious food (Figure 1) is essential for energy, metabolism, health, fitness, growth, and tissue repair. In the context of weight training, it is very important for providing adequate fuel for your workouts, and helping your body to recover and grow from exercise. Your workouts will damage your muscles. Your diet must provide the raw materials necessary to repair them, as well as build the muscles to make them stronger and less susceptible to damage.
The food you eat will significantly affect your results. For weight training success, it is essential to understand at least the basics of nutrition. Following nutritional guidelines will help you to achieve your goals, whether they are to maximize muscle growth (hypertrophy), lose weight, maintain weight, gain weight, or minimize the storage of fat during a bulking phase (that is, a period during which you consume an excess of calories to promote maximum muscle growth).
What do you need to know?
Gaining an understanding of good nutrition boils down to learning about seven key subjects:
- Dietary fat
- Carbohydrate (including dietary fiber)
- Dietary minerals
Nutrients are the substances in foods needed for health and nourishment. Carbohydrate, protein, dietary fat, and water are called macronutrients (“large nutrients”) because they are needed in large amounts. Vitamins and dietary minerals are termed micronutrients (“small nutrients”) because they are needed in small amounts.
Protein (Figure 2) is essential for growth, immune function, and the construction of hormones and enzymes. It is used to repair, maintain, and build the muscle fibers that are damaged during workouts, and can also act as an energy source in the absence of carbohydrate. To build muscle, you have to consume more protein than your body breaks down. An insufficient intake will result in slow strength and size gains or even loss of muscle!
Dietary fat provides the most concentrated source of energy. It is vital for absorbing certain vitamins (A, D, E, and K), maintaining cell membranes, and building muscle. Fat plays a vital role in the manufacture of testosterone, which is important for promoting muscle growth and increasing strength. Fat may also help to increase levels of insulin-like growth factor (IGF-1), another key hormone that stimulates growth in muscle and strength.
Carbohydrate (Figure 3) is your body’s main source of fuel. If you don’t eat enough carbohydrate, when you exercise, you’ll fatigue sooner, and your muscle and strength gains will be reduced. On the other hand, if you eat too much carbohydrate, it will be stored as fat.
Dietary fiber is a carbohydrate that is incompletely absorbed by your body. It helps to keep your digestive system healthy by increasing the size and weight of your stool and helping it to move through your digestive tract.
Water makes up nearly two-thirds of your body. It is important for maintaining the balance of bodily fluids, which is essential for every function and chemical reaction that occurs within your body. For example, water is used to transport nutrients in, and waste products out, of cells. It is necessary for proper digestion, absorption, circulation, and excretion, as well as the assimilation of water-soluble vitamins. Water also helps to maintain proper body temperature. Because it is lost as sweat during exercise, water must be adequately replenished.
Vitamins are organic chemical compounds that the body can’t synthesize in sufficient quantities and must therefore obtain from the diet. Common vitamins include Vitamin D (which helps the body to absorb calcium, iron, magnesium, phosphate, and zinc from food) and Vitamin C (which is important for proper growth and development, the maintenance of the immune system, and good vision).
Dietary minerals are inorganic chemical elements required by the body other than the four elements carbon, hydrogen, nitrogen, and oxygen. Some dietary minerals, such as iodine and fluoride, are only needed in tiny quantities. These are known as trace elements. Iodine is necessary for normal thyroid function and for the production of thyroid hormones. Fluoride helps to prevent tooth decay. Other dietary minerals, such as iron and calcium, are needed in larger amounts. These are known as macrominerals. Iron is essential for numerous processes, including making the oxygen-carrying proteins hemoglobin and myoglobin. Calcium is important for strong bones and teeth.
Calories are the units of energy found in nutrients. Your body needs a certain number of calories each day to survive, remain healthy, and fuel physical activity. If you consume fewer calories than your body needs, you will lose weight; if you consume more calories than your body needs, you will gain weight. Therefore, being aware of the number of calories you take in is important, and can help you to manage your weight.