I have no problem with the "calories in = calories out" statement. Thermodynamics says it must be true. If calories in <> calories out it doesn't mean the law

I have no problem with the "calories in = calories out" statement. Thermodynamics says it must be true. If calories in <> calories out it doesn't mean the law of thermodynamics is wrong, it means you have a leak somewhere in the lab you must plug before you can test hypothesis such as "eat less and you will lose weight".