The way in which you lose weight may contribute to unintended and unwanted changes in physical appearance. Weight loss resulting in diminished health and fitness levels may lead to decreased height.Food intake and energy output are measured in calories. When the amount of calories eaten is less than the amount of calories used for energy, the extra energy is generated from stored body fat. This results in reduced excess body weight. For improved health with weight loss, the Centers for Disease Control and Prevention recommend a weight loss of no more than 1 to 2 pounds per week.Weight loss due to a very low-calorie diet, products that have a diuretic effect, or high-protein, low-carbohydrate food plans may cause an initial weight loss of up to 10 pounds in the first two weeks. Weight loss may be due to significant water and mineral loss, affecting bone health. Diets low in vitamin D and calcium can cause osteopenia, a condition in which bones become weak. Over time, osteopenia can klead to severe bone loss, which can decrease height.Your body reaches peak height up to age 40. From there, your height may decrease by up to two inches between 50 and 80, says the AGS Foundation for Health and Aging. Decreases in fluid between vertebrae cause your spine to compress and your torso to shrink. As your bones weaken, the arches in your feet begin to flatten, contributing to decreases in height, Medline Plus says. Diminished bone density due to aging contributes to postural problems, resulting in a postural slump. Though these factors cause height decreases because of aging, they can also occur as result of bone and mineral loss from an unhealthy weight loss.Developing osteopenia also increases the chance of developing osteoporosis, a condition in which further weakening of the bones makes them fragile and susceptible to fractures. Risk factors include being female, being thin and consuming diets low in Vitamin D and calcium. Nutritional disorders such as anorexia nervosa and smoking increase the chance of decreased bone density. Prevention of bone loss is possible with adequate intake of foods with vitamin D and calcium, maintaining a healthy weight and weight training. The American Dietetic Association recommends a daily intake of 1000 milligrams of calcium and 400 international units of vitamin D.Weight loss that was unintended, combined with additional problems such as decreases in height, may be indicative of more serious health problems. If this happens, see a doctor.