Things to keep in mind when you hop on the scale.
Water normally constitutes about 60%-70% of our body weight. So, for a 150 pound person, water accounts for about 100 pounds, and for a 300 pound person, water accounts for about 200 pounds. Variations in body water weight can be caused by several factors, including mineral imbalances, changes in lean body mass (muscle contains more water than fat), and a variety of toxins. Many folks that begin a weight loss program are familiar with the rapid “water-loss” phenomenon .
Another wild card in the weight game is “parasites,” by which I mean living organisms hosted by the body, including bacteria, viruses, nematodes (worms), and fungi. They are all hungry, with a desire to grow. It would be easy to dismiss parasites as insignificant, but we still have much to learn in this area.
Some parasites are essential to health, such as commensal gut bacteria, which weigh several pounds in a healthy person. A big unknown is fungi, and our understanding of its role in human health is rather pathetic. Fungal masses are known to form in the sinuses and the gut, and who knows where else.
Bottom line: some changes in scale weight can be totally unrelated to caloric balance.