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Weight Loss and Lean Body Mass
➤ Although lean mass loss typically accounts for 15% to 25% of total
weight loss, it is not yet determined whether the loss of lean mass
corresponds to a genuine reduction in muscle tissue. There is
insufficient evidence regarding alterations in cardiorespiratory
fitness and objectively measured physical function. Nevertheless,
incorporating resistance or strength training into a comprehensive
PA plan may theoretically enhance muscle quality and function.
Energy Expenditure: Calories
➤ A calorie is the amount of heat energy required to raise the
temperature of 1 gram of water one degree Celsius.
➤ A Calorie (capital "C") is the same as kilocalorie, which is the heat
energy required to raise the temperature of one kilogram of water
by one degree Celsius.
➤ One kcal = 4.184 kilojoules.
➤ Kilocalories are used in food labels, usually expressed as Calories.
➤ When referring to food or physical exercise, it is common that the
term "calorie" actually refers to kilocalorie (kcal).
➤ "3500 Calories per pound of weight (loss or gain)" is a common
energy content approximation, which is technically inaccurate
but a reasonable "rule of thumb".
➤ Additionally, during negative caloric balance, dynamic
adaptations in body energetics occur (changes in resting
metabolic rate, skeletal muscle efficiencies) resulting in the need
for greater energy expenditure and/or further reduction in energy
intake in order to achieve the same rate of weight loss.
