Losing weight without making a conscious effort to diet may happen without warning and may or may not be a cause for concern. Some of the common reasons for losing weight without dieting are the presence of an underlying illness and possibly, unintentional changes in eating habits. If you're losing weight rapidly or notice a significant change in weight, contact your physician.
A recent infection can cause a noticeable drop in weight. Infections can be viral, bacterial, fungal or parasitic in nature. Among the infections known to cause a loss of weight include tuberculosis, HIV and parasites such as tapeworms. A food-borne illness can cause a drop in weight because you’re more likely to have symptoms of diarrhea or vomiting. Typically if the infection is treated, weight loss will cease so it’s important to see physician if you think you may have an infection.
Disease and Weight Loss
Diseases can cause a dramatic shift in weight, especially if the disease is progressive. Diseases such as cancer can cause weight loss in many patients. Gastrointestinal diseases can cause weight loss due to the malabsorbtion of nutrients or the changes in appetite they can cause. Endocrine disorders such as diabetes, hyperthyroidism and hypocalcemia can also cause weight loss.
Changes in Activity Levels
If you have recently changed your activity, weight loss may occur. If you normally don’t move around a lot or have a desk job that requires you to sit for extended periods, any increase in activity can cause you to lose weight -- especially if you are sedentary. According to the American Council on Exercise, increases in exercise including participating in a new sports activity, weightlifting, running, housework or running more errands can all contribute to weight loss because you're starting to burn more calories than you're eating.
Changes in Appetite and Eating Habits
Sometimes you can be unaware of a change in appetite, which means you’ll be eating fewer calories unconsciously. Appetite can be affected by stress, illness or infections. If you have recently taken on more work or have less time to eat due to certain obligations, you may find it more difficult to eat throughout the day. Many people get so caught up in what they're doing, they skip meals completely. Although you may not be making a conscious effort to diet, it's still possible that you might forget to eat or not even feel like eating. Both can cause weight loss.