Food energy is energy that animals (including humans) derive from their food, through the process of cellular respiration, the process of joining oxygen with the molecules of food (aerobic respiration) or of reorganizing the atoms within the molecules for anaerobic respiration.
Humans and other animals need a minimum intake of food energy to sustain their metabolism and drive their muscles. Foods are composed chiefly of carbohydrates, fats, proteins, water, vitamins, and minerals. Carbohydrates, fats, proteins, and water represent virtually all the weight of food, with vitamins and minerals making up only a small percentage of the weight. Carbohydrates, fats, and proteins comprise ninety percent of the dry weight of foods. Food energy is derived from carbohydrates, fats and proteins as well as organic acids, polyols, and ethanol present in the diet. Some diet components that provide little or no food energy, such as water, minerals, vitamins and fiber, may still be necessary to health and survival for other reasons. Water contains very stable chemical bonds and so cannot be oxidized to provide energy. Vitamins and minerals are present in very small amounts (in milli- or micrograms) and also cannot be used for energy. Fiber, a type of carbohydrate, cannot be completely digested by the human body. Ruminants can extract food energy from the respiration of cellulose thanks to bacteria in their rumens.
A sedentary lifestyle is a type of lifestyle with no or irregular physical activity. A person who lives a sedentary lifestyle may colloquially be known as a couch potato. It is commonly found in both the developed and developing world. Sedentary activities include sitting, reading, watching television, playing video games, and computer use for much of the day with little or no vigorous physical exercise. A sedentary lifestyle can contribute to many preventable causes of death. Screen time is the amount of time a person spends watching a screen such as a television, computer monitor, or mobile device. Excessive screen time is linked to negative health consequences.
A lack of physical activity is one of the leading causes of preventable death worldwide.
The Schofield Equation is a method of estimating the basal metabolic rate (BMR) of adult men and women.
It is commonly used by dietitians as a means of estimating the total energy intake required to maintain current body mass. This figure can then be used to design a dietary regime that places the subject in kilojoule (or kilocalorie) deficit or surplus, depending on whether weight loss or gain is the intended clinical outcome.
The freshman 15 is an expression commonly used in the United States that refers to an amount (somewhat arbitrarily set at 15 pounds) of weight often gained during a student's first year at college. In Australia and New Zealand it is sometimes referred to as First Year Fatties, Fresher Spread, or Fresher Five, the latter referring to a five-kilogram gain.
The purported causes of this weight gain are increased alcohol intake and the consumption of fat and carbohydrate-rich cafeteria-style food and fast food in university dormitories. Many dining halls in American universities are all-you-can-eat style and offer copious dessert choices. In addition, lack of sleep may lead to overeating and weight gain, because it lowers the level of leptin. Other causes include malnutrition, stress, and decreased levels of exercise. All of these factors can affect each person in a different way. Studies confirm many of these causes. Colleges and universities have recently been cracking down on this common problem and are trying to educate people on how to prevent it. This problem has grown so much that students are focusing on how to stop the freshman 15 before it happens.