In response to Hodgson's article on Robert Lustig's diet advice ("Obesity — How'd THAT Happen?" Jan. 22), Barry Evans defended the validity of the First "Law" of Thermodynamics ("Field Notes," Jan. 29). We do not live in a theoretically perfect world, however, and using an incomplete description of this theorem without including losses to other energy types, such as friction, is as misleading as religious and political dogma.
Barry is interested in wastewater treatment plants, so he should be able to realize why human waste (even after the human has exercised), aka sewage, has a significant biological oxygen demand and needs to be treated to avoid polluting because of the remaining amount of "calories." To be crude, why do some turds float?
Studies by endocrinologists and organic chemists are more reliable and consistent than the office-football-pool-type questionnaires used by many dieticians.
Charles Wilson, Orick