Work stress and bad sleep and eating habits really take the fire out of your fat-burner. “The key to avoiding weight gain is to pack on more lean mass,” says strength coach and gym owner Jim Smith. “That boosts your resting metabolism, which helps you burn more fat even when you’re not exercising.” Stay slim with this muscle-maximising workout.

DO THIS

Perform each pair of exercises as a superset (back-to-back). Do each superset three times, resting for 30 seconds after the first exercise and 60 seconds after the second.