Quiz 7: Energy Balance and Weight Control


The energy requirements of an average women ranges from 1800 to 2400 kcal and for men it is 2200 to 3000 kcal per a day. A goal of losing 1 pound of body weight per a week needs to restrict the calorie intake to 1200 kcal for women and 1500 kcal for men. Thus, an energy deficit of 100 kcal per day would result in a total weight loss of about 10 pounds over a period of 3 years. Thus, the correct option is (d). 3 years. It takes 3 years to lose 10 pounds of body weight with excluding 100 kcal per a day. Thus, the options (a), (b) and (c) are incorrect.

The rate of metabolism, energy expenditure, differences in brain chemistry is determined by the genes. In a research experiment, identical twins grown in two different regions showed similar patterns of weight gain irrespective of differences in their food intake. This explains that the food habits are dominated by the nature in determining the fat distribution. Our body type is also determined by the gene type, that's why some people are thin; some are tall, others look obese etc.If the gene pool has not been changed from a long period, we can observe a similar pattern of influence of environmental factors such as different food habits on body shape. The food habits such as fatty diet play a major role in shaping our body. People who are not genetically linked may show same pattern of body shape if their food habits are similar. Sedentary life styles, eating refined and fast foods, childhood obesity, stress, excess weight gain during pregnancy are the risk factors of developing obesity in females. So, both genetic factors and environmental conditions determine the body obesity.

All energies required by the body are broadly classified into four categories based on the purpose for which they are used. Thus, the total energy used by the body is derived broadly from: 1. Energies used when the body is resting (basal metabolism). 2. Energies when the body is performing some physical activity. 3. Energies used to perform the activities involved in processing food (thermic effect). 4. Energies involved in regulating body temperature (thermogenesis). All energies used by the body will fall into one of these four types of energies. Energies involved in individual activities such as chewing food and peristalsis, cannot by itself represent thermic effect because there are other activities that expend energy as part of the thermic effect. Chewing food and peristalsis form only a small part of various activities that expend energy contributing towards thermic effect and cannot fully represent that category. The energy expended during resting or keeping the awake body alive is referred to as basal metabolism. This does not include the energy expended in processing food.Hence, options 'a', 'b', and 'c' are incorrect. Energy expended in excess of the that required for resting mechanism and not including that due voluntary physical activity or thermoregulation, falls under thermic effect. These are the energies that increase the metabolic rates after ingestion of food such as digesting, absorbing and packaging nutrients. Therefore, the correct option is option img .