It's 3pm. Classes are finished, school is out and you've got about an hour before your sports game. Feeling a bit hungry, you stop off at the nearby corner store to grab a quick bite.
Looking at the usual array of food, you notice a different kind of snack: protein bars. Brands such as Bio-X, Proteins Plus, and Muscle Tech are all marketed as high protein supplements, typically for athletes. But what are they really meant to do?
What's in a protein power bar?
To understand the purpose of protein bars, it's important to first take a look at what proteins are and why we need them. Proteins are the major structural component of all cells in the body. They are important for functions such as repairing muscles (like those damaged from sports), making red blood cells needed to transport nutrients, and keeping organs healthy.
Proteins are made up of building blocks called amino acids. There are twenty amino acids, eleven of which your body can make on its own. The other amino acids must be taken in from the diet and are known as essential amino acids. Your body needs all 20 to function properly.
Did You Know?
Amino acids are linked to each other by peptide bonds Protein is high on the list of ingredients of protein bars, and typically comes from whey, egg, casein or soy sources. These are "complete" protein sources since they contain all the essential amino acids. Protein bars also tend to contain carbohydrates, fat, vitamins and minerals, but are usually low in fibre.
Do they improve your performance?
Protein bar manufacturers usually state that protein is most important for athletic performance such as building muscle mass to increase strength or enhancing energy.
Since proteins are important in building and repairing muscle, you may think that the more protein you consume, the bigger and faster you'll develop muscles. Protein alone won't produce this effect. It is only protein in combination with strength training and physical exercise that you will develop bigger, stronger muscles.
Did You Know?
The word muscle comes from the Latin word musculus which means "little mouse" — it was thought that muscles, like biceps, pop up as though a mouse were scurrying about under the skin Protein also makes a very small contribution to energy supply in exercise. The main fuels used by exercising muscles are fats and carbohydrates (now you can see why the protein bars also contain carbohydrates and fats in the ingredient list).
But, if carbohydrates run low, such as during extensive workouts, proteins in tissues, such as the muscles, can be converted to glucose (sugar) and burned for energy. In this way, carbohydrates prevent proteins from being degraded for fuel and allow them to be used for building muscle.
Can too much protein be a bad thing?
Protein that is not used by the body for metabolic functions or for energy production is stored as fat.
Consuming excess protein can also have harmful effects on the body. When protein is broken down into individual amino acids, toxic ammonia is produced. This is normally converted to safer nitrogen which is then excreted in urine.
But too much nitrogen can still cause problems such as increasing the risk of dehydration and fatigue. With protein bars providing anywhere from 15 to 35 grams of protein per bar, it's easy to get in excess of protein requirements.
Should you go ahead and grab a protein bar?
It's true that athletes need slightly more protein then less active teens. But, the average Canadian diet is normally high enough in protein to cover most protein requirements for athletes.
So, for most healthy exercising teens, it's likely that the protein in normal meals will be enough to stimulate muscle growth, and a protein bar isn't really needed. Good sources of protein are fish, lean meats and poultry, eggs, dairy, nuts, soy, and peanut butter.
Did You Know?
Protein has 4 calories per gram. So, a typical 2,000-calorie diet would allow for 50 grams of protein Ideally, it's best for active teens to eat a varied diet, and including a range of protein foods. This will ensure that you keep your blood glucose up, and will keep you kicking that soccer ball and completing that race to the best of your ability, as well as helping your muscles to recover.
So, the next time you've got the after-school nibbles before a sports practice or game, instead of protein bars, why not try reaching for a tuna sandwich or yoghurt and crackers?
Canada's guide to healthy eating and physical activity
University of Alberta Health Information
Mina is a medical copywriter based in the UK. When she's not creating advertising campaigns, she's happily pottering around her kitchen, coming up with new recipes for gourmet desserts.