workout .. I suspect that my Sg workout is more than U.S. workout, in terms of calorie burned, and my Sg calorie intake is similar to U.S.

base metabolic rate .. Perhaps the base metabolic rate is lower in Sg, but I have no evidence.

water weight .. Perhaps my body retains more water in Sg than in U.S.

We don’t know the exact calorie numbers. It’s possible that in SG the measurable calorie in my diet is similar to U.S., but the energy extracted by the body is a higher percentage.