Regular body composition measurements will indicate if the calorie level should be changed
or not. Most individuals should be able to sustain a fat loss of 1-1.5 lbs of fat per week. If fat loss
is occurring at less than 1 pound per week, calories can be reduced slightly (or aerobic exercise
increased). It is rare to find anyone who can lose 2 lbs of fat per week consistently without losing
muscle as well. Anyone losing more than 2 pounds of weight per week should increase calories or
decrease aerobic activity to avoid muscle loss.
The maximum allowed deficit
The effects of exercise at different calorie levels on fat loss vary and are discussed in
chapter 22. In general, the studies support the idea that there is a threshold deficit where
maximum fat loss will occur with minimal changes in metabolic rate. This threshold occurs at
approximately 1000 calories per day below maintenance and represents the maximum allowed
deficit. As a general rule, the total daily deficit, created through caloric restriction and exercise,
should be no greater than 1000 calories total per day. This should yield an average fat loss of 2
pounds per week. Some exceptions to this rule are discussed in chapter 13.
This 1000 calories per day deficit can be created through a variety of combinations of
caloric restriction and exercise. If an individual prefers to eat more calories (such as eating at
maintenance levels), they would need to do an extensive amount of exercise to generate a 1000
calorie/day deficit. By the same token, if an individual is involved in an activity (such as long
distance running or cycling) that has them expending 1500 calories/day through exercise, they
will need to increase calories by 500 calories above maintenance to avoid surpassing the 1000
calorie/day threshold.
For some individuals, even 1000 calories/day may be too great of a deficit. This is
especially true for lighter individuals, for whom a 1000 calorie/day deficit may take their caloric
excessively low. Arguably a better approach is to use a smaller caloric deficit with increased
activity and aim for a sustainable and safe fat loss of 1-1.5 lbs of fat per week. While the
ultimate bodyfat/bodyweight goal will take longer to achieve, it should be easier to sustain as
there is less tendency for metabolic rate to decrease.
To summarize: dieters should initially create a net deficit (exercise plus caloric restriction)
of approximately 10-20% below maintenance. For the average person, this means a caloric
intake of 12-13 calories/lb of bodyweight with moderate activity levels. After 2 weeks, depending
on total fat loss, the total deficit can be increased, to a maximum deficit of 1000 calories per day.
Weight Gain
For weight gain to occur, a calorie excess is needed to support muscle growth. There is
little research into the number of calories needed to meet maintenance levels as well as allowing
for muscle growth to occur.
A good starting point is to increase calories by 20% over maintenance. This gives an
approximate calorie intake of 18-19 calories/day although many individuals may require much
higher calorie levels (above 20 cal/day). Obviously muscle gain is predicated on performing weight