Fast food constitutes high content of fat, sodium, and sugar and have been categorized as bone robbers. The main reason that you should avoid fast food is that it doesn't maintain nutritional balance as it is not easy to have control over how they are cooked. Some fast foods are with lots of oil and butter (without any guarantee of purity) and there may be no option if you want this selection with reduced fat. Fast food generally tends to be short on fresh fruits and vegetables. Soda pop and cola drinks contain considerable amounts of phosphorus, an acid-forming mineral in the body. Research has shown that phosphorus can interfere with the skeleton’s ability to absorb calcium. A recent study reported in the Archives of Pediatrics and Adolescent Medicine suggests that teenage girls who drink lots of soda may increase their risk of developing bone fractures and osteoporosis. These drinks also contain large amounts of refined sugar or equally dangerous sugar substitutes, which further encourage bone loss. During the teenage years, when 40 to 60 per cent of peak bone mass is built, a natural whole foods diet, free of bone-robbing soft drinks, is most important.
The researchers also concluded that a diet high in fast foods will increase a person's risk of weight gain and obesity - even though they may feel that they are eating no more than they would if they ate an average meal. The difference between a fast-food meal and a home-cooked one is the sheer quantity of calories and fat it delivers in one go. The US Department of Agriculture's recommended daily intake for a normal adult male is 2800 kilocalories (11,723 kilojoules) and a maximum of 93 grams of fat. A meal at a fast-food outlet - burger, fries, drink and dessert - can deliver almost all of that in a single sitting. Biologists are now starting to realize that a binge of these proportions can trigger physiological changes which mute the hormonal signals that normally tell you to put down the fork.
Under normal conditions these hormones control eating and help maintain a stable body weight. Leptin, for example, is continuously secreted by fat cells and its level in the bloodstream indicates the status of the body's fat reserves. This signal is read by the hypothalamus, the brain region that coordinates eating behaviour, and taken as a guideline for keeping reserves stable. The problem is, people who gain weight develop resistance to leptin's power, explains Michael Schwartz, an endocrinologist at the University of Washington in Seattle. "Their brain loses its ability to respond to these hormones as body fat increases," he says. The fatter they get, and the more leptin they make, the more insensitive the hypothalamus becomes. Eventually the hypothalamus interprets the elevated level as normal - and forever after misreads the drops in leptin caused by weight loss as a starvation warning.