According to The Obesity Society, 64 percent of American adults are overweight with 31 percent of them considered obese. Subsequently, many people are trying to lose weight by dieting, exercising, surgery, drugs or a combination of weight loss methods. Despite the fact it may have taken years to gain weight, many people try to lose weight too quickly by overexercising or following very-low-calorie or crash diets. Crash diets may result in rapid initial weight loss but may have a negative effect on long-term health and diet compliance.
Fat Mass and Signaling Hormones
Your body fat levels are directly proportional to a signaling hormone called leptin. Leptin levels are monitored by the hypothalamus section of your brain. Leptin controls appetite, modulates your metabolism and promotes fat burning. If fat levels drop very quickly, there is a subsequent rapid drop in leptin levels. A rapid drop in leptin levels will trigger the starvation response.
The Starvation Response
The starvation response is the term used to describe what happens within your body as a result of rapid drops in leptin. The starvation response causes a reduction in your daily energy expenditure by lowering your metabolism, increasing hunger and also prompting the breakdown of muscle for energy. In addition, the starvation response works to ensure you regain not only the fat you have lost, but also some extra fat to protect you from similar bouts of food restriction. This results in a cycle of weight loss/weight gain often referred to as yo-yo dieting.
Very-low-calorie diets that result in rapid weight loss are often dangerously low in essential nutrients, including vitamins and minerals. A lack of vitamins can lead to a host of health problems, including immune system suppression and bad skin, hair and nails. Chronic mineral deficiencies may also have long-term effects on your health. A lack of essential minerals can lead to fluid imbalances, cardiac arrhythmia or an irregular heart beat, muscle cramps and loss of bone mass.
Very-low-calorie diets may result in a rapid initial weight loss but many dieters find that the severe hunger associated with eating so little food makes it hard to stick with this type of eating program for long periods of time. Hunger levels may become so severe that the dieter falls into a diet/binge cycle of eating. Crash dieting may lead to eating disorders like anorexia and bulimia. A very-low-calorie diet can also be socially exclusive, especially if friends and family are eating normally.
Safe Weight Loss
To avoid losing weight too fast, most diet experts agree that a moderate reduction in food intake combined with a moderate increase in physical activity is best. By eating 250 fewer calories per day and engaging in exercise that results in 250 extra calories being burned there is a net loss of 500 calories per day, or 3,500 per week. This will result in a weight loss of around 1 pound per week. This slow and gradual weight loss will be sustainable, will not trigger the starvation response and will have no negative impacts on your health.