When applying the First Law of Thermodynamics to hypertrophy in a hardgainer, what specific quantitative adjustment should be made to the caloric surplus when progress stalls without a corresponding increase in activity or lean mass?

When applying the First Law of Thermodynamics, which states that energy cannot be created or destroyed but only transformed, to the biological system of a hardgainer aiming for hypertrophy, a caloric surplus is essential. Hypertrophy, the increase in muscle cell size, requires a net positive energy balance, meaning energy intake must exceed energy expenditure to fuel protein synthesis and provide the raw materials for new tissue. A hardgainer is an individual who typically has a higher Total Daily Energy Expenditure (TDEE) relative to their body size and activity level, often due to elevated Non-Exercise Activity Thermogenesis (NEAT) or a higher intrinsic metabolic rate, making it challenging for them to consistently achieve and maintain a sufficient caloric surplus for weight and muscle gain. When progress stalls, meaning there is no further increase in body weight or lean mass, and this occurs without a corresponding increase in physical activity or the metabolic demands of newly acquired lean tissue, it indicates that the current caloric intake has become equal to or is now falling below the individual's actual TDEE. To re-establish the necessary positive energy balance for hypertrophy, a specific quantitative adjustment to the caloric surplus must be made. The caloric intake should be quantitatively increased by an additional 250 to 500 kilocalories per day above the current intake that led to the stall. This increment aims to re-create a thermodynamically favorable environment for muscle growth, providing the energy differential required to overcome the hardgainer's elevated energy expenditure and support the energetic demands of muscle protein synthesis, targeting a modest rate of weight gain typically between 0.25% to 0.5% of body weight per week, which is conducive to lean mass accretion.