Blundell, R. (2011). BlackBerry Nutrition Apps [Photograph]. Retrieved from http://crackberry.com/food-and-nutrition-tracking-applications-blackberry-smartphones-and-playbook-0
The Importance of Food
You're sitting in your distance-learning Environmental Science class as you feel your stomach give a mighty rumble. You're hungry - your body has run out of fuel. Yet you rough it out until lunch, at which point you devour your chicken salad sandwich and feel much better.
What just happened?
The human metabolism uses calories from food to provide energy to carry out the day's activities. Food contains proteins, carbohydrates, and fats that carry out the vital processes of reconstruction, growth, development, and repair in the human body. Food even supplies the body with 45 components that cells cannot produce on their own! We reap the benefits of good nutrition because of the processes of ingestion, digestion, absorption, assimilation, and egestion. In a nutshell, food is broken down into its essential components within the body through the process of digestion; nutrients are then absorbed into the blood stream and distributed to different parts of the body through systemic circulation within blood vessels. Systemic circulation is the process by which blood acts as a "conveyor belt" for oxygen and nutrients. In this process, oxygen-rich blood deposits the nutrients into capillaries in the human body, enabling us to replenish our essential nutrients and carry out cellular processes. This section will explain the biology of nutrition and describe common disorders, diseases, and ailments that result from nutrient deficiencies and/or excessive eating. It will also describe the influences of culture, religion, and societal expectations and norms on the consumption of food.
So, not quite.....
Thaaat's better.
Calories = Energy!
What's a Calorie?
You may have heard people say, "I don't want this burger/soda. It's like, a million calories or something!!" In your head, you mentally tick that person off as someone who is paranoid about weight and will probably psychoanalyze everything you eat. However, when Nicholas Clement wrote of a 'calorie' in 1824, that's not quite the definition he was thinking of. A calorie is an SI unit to describe the amount of ENERGY required to increase the temperature of one gram of water by one degree Celcius. Since fats have the highest concentration of calories and provide the most energy, they are related concepts. You, as a human being (as opposed to...not being human) require about 1000 - 1400 calories per day for crucial organs like the heart and lungs to function. Beyond this, it's subjective - you might need 2000 extra calories for your day-to-day life or 600 calories instead, depending upon your metabolism.
Why Eating is Always Advised
Wikipedia (2006). USADA Food Pyramid [Photograph]. Retrieved from http://en.wikipedia.org/wiki/File:USDA_Food_Pyramid.gif
Food contains several components that keep us going. The human body is an amazing machine that requires fuel and nourishment. What are these components, you ask? Take a look!
Carbohydrates: Carbohydrates provide most of the energy in the body, and carbohydrates are one of the first components to be broken down by the enzyme called salivary amylase in the mouth. All carbohydrates are absorbed as glucose and sent through the bloodstream. Carbohydrates that are not used for energy purposes are stored in the liver and skeletal muscle as glycogen. Simple carbohydrates are what we call "sugars" - they are naturally occurring in fruit and milk but are also found in chocolate, sugar, cake, sweets, and soft drinks. They are easier to break down in the body although they are unhealthy because they lack minerals and vitamins. Complex carbohydrates are found in grains such as pasta, bread, lentils, barley, potato, and corn. In other words, complex carbohydrates tend to be staple food whereas simple carbohydrates tend to be the composition of the sodas and the candy you are normally advised against. Proteins: The protein we consume on a day-to-day basis comes from meat, fish, milk, vegetables, pulses, and nuts. When your mom looks at your plate and scolds you to eat your greens, she isn't kidding! Protein is often described as the most essential component of food because it is necessary for DNA/RNA transcription and translation as well as the formation of connective tissue, enzymes, and cellular reactions. Proteins are made up of amino acids, which are like building blocks; certain amino acids cannot be produced by the human body. Eat those greens!
Lipids: Fats provide approximately 9 calories of energy per gram, which is greater than the 4 calories provided by carbohydrates and proteins combined. The energy that fat provides is often dissipated into heat. Fats are also called lipids; they are instrumental in the formation of cell membranes and ensure the functioning of the nervous system. There is saturated and unsaturated fat; although fats are usually described in a negative sense, there is no denying the role that this component plays in the human body.
Vitamins and Minerals: Vitamins and minerals need to be consumed because they serve as catalysts for certain cellular reactions and provide some of the inorganic nutrients of the body. Although these components are often brushed off as insignificant, the important thing to remember is that, in the human body, NOTHING is insignificant; each component has its place in a reaction or process. Vitamins and minerals are essential components needed in small amounts.