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Students spend only 14 percent of their time in school.

With knowledge of how people learn, teachers can choose more purposefully among techniques to accomplish specific goals.

Depictions of eukaryotic RNA regulation in 1994 and less than 15 years later. (a) At a time when the understanding of genetic information was still largely based on bacterial studies (upper left), proteins were thought to perform all the functions in cells, including regulation (arrow 1, black) in eukaryotic cells, with speculation about a possible role of RNA in gene regulation represented as a question mark (arrow 2, red). (Reproduced from Nowak⁸⁴⁴ with permission from the American Association for the Advancement of Science.) (b) After the turn of the century, many additional examples of regulatory RNAs emerged and shown to act in many levels of gene expression in the nucleus and cytoplasm of eukaryotic cells. (Reproduced from Amaral et al.¹⁸⁰ with permission from the American Association for the Advancement of Science.)

Energy balance Weight maintenance occurs when energy input equals energy expenditure, with gains and losses occurring when there is an imbalance. A gain of one pound occurs when approximately 3,500 calories are consumed in excess of energy needs. For most individuals, resting metabolic rate (RMR) comprises the major component of energy expenditure, accounting for 60-75 percent of energy needs (IOM, 2005; Pi-Sunyer, 2000). Resting metabolic rate is largely governed by lean tissue, which has a higher metabolic rate than adipose tissue. Neoplastic tissue also may have a higher metabolic rate, though a study of 200 cancer patients compared to 200 healthy controls found that metabolic rate was highly variable among cancer patients (50-175 percent of predicted values) and greatly influenced by tumor stage and site (Knox et al., 1983). Speculation also exists that RMR may be influenced by various cytokines, though more research is necessary (Pi-Sunyer, 2000). The Thermic Effect of Food, also known as Specific Dynamic Action, is the energy needed for digestion and metabolism of food—transient energy needs that go above and beyond normal metabolism. The Thermic Effect of Food accounts for only 5-10 percent of energy needs and is dependent upon the magnitude of dietary intake, and also may be influenced by the consumption of specific foods or food-related substances. For example, tea, capsaicin, and caffeine may increase metabolism even further (Bell and Goodrick, 2002), though more studies are needed to determine if these transient increases are clinically meaningful. Physical activity comprises the third component of energy expenditure and for individuals living in the developed world, usually accounts for 15-30 percent of energy needs. The energy expended for physical activity is the most modifiable component of energy expenditure. Furthermore, given the potential of exercise (especially resistance training) to increase lean body mass, physical activity also may act indirectly to increase RMR.
SOURCE: Demark-Wahnefried presentation (October 31, 2011). Reprinted with permission from Wendy Demark-Wahnefried.