Comment by paulpauper

It def. adds up. To get an idea, consider cancer cachexia , which is involuntary weight loss due to cancer. Weight loss in the setting of cancer is not just due to appetite loss from side effects of treatment and sickness, but also from metabolic changes. It's such weight loss that brings the cancer to the attention of the doctor, and can be quite dramatic despite the patient not changing his or her appetite or other routine or feeling sick at all. How much of an energy deficit is this? it's believed that cachexia only causes a deficit of only 200 calories/day, but this enough to produce dramatic weight loss.