Nutrition: A Very Short Introduction (Very Short Introductions)
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In this Very Short Introduction, David Bender explains the basic elements of food, the balance between energy intake and exercise, the problems of over- and under-nutrition, and raises questions on the safety of nutritional supplements.
Looking broadly at what constitutes nutrition, Bender provides insight into a topic of wide interest and importance in today's world. With a look at diet in relation to nutrition, this Very Short Introduction provides an overview of the biochemistry of nutrition and the health risks associated with poor nutrition- including obesity and types of food allergies. It provides an essential guide to effectively understand the principles of, and necessary reasons for, a healthy diet.
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exercise. At the same time, with some very obvious exceptions, most work is now less physically demanding than it was half a century ago. There is increased mechanization in factories, more jobs are sedentary, with less need to walk around an office or factory. Automated washing machines need far less effort than doing laundry by hand; powered hedge trimmers and lawn mowers reduce the physical exertion of gardening. How can overweight people lose weight? There is an apparently simple answer to
work by physical activity ratio (PAR) 4 Energy yield and oxygen consumption in oxidation of metabolic fuels 5 Guidelines for percentage of energy from fats, carbohydrates, and proteins in a prudent diet, compared with average Western diets 6 Minerals classified by their functions in the body 7 Labelling reference intakes and tolerable upper levels of habitual intake of vitamins and minerals for adults Acknowledgements I am grateful to Gary Bateson, Kenneth Bodman, and Carol Farguson, three
electrical stimulation leads to feeding even if the person has eaten enough. Similarly, destruction of the satiety centres leads to uncontrolled eating, and electrical stimulation leads to cessation of feeding, even in someone who is physiologically hungry and in the fasting state. These appetite control centres have links to other brain regions. The amygdala controls learnt food behaviour—in other words, knowing that something is a food, as opposed to non-food. A young child will put almost
traditional oriental condiments that is often used in manufactured foods. The other instinctively pleasurable taste is sweetness, which permits the detection of carbohydrates, and hence energy sources. While it is only sugars (and artificial sweeteners) that taste sweet, human beings (and some other animals) secrete the enzyme amylase in saliva, which catalyses the breakdown of a small amount of starch, the major dietary carbohydrate, to sweet-tasting sugars, while the food is being chewed. The
By contrast, in developing countries the availability of food may be a major constraint on what people choose. Even in developed countries, the cost of food is important, and for the more disadvantaged members of the community, poverty may impose severe constraints on their choice of foods. Religious and ethical considerations are important in determining the choice of foods. Observant Jews and Muslims will only eat meat from animals that have cloven hooves and chew the cud. The terms kosher in