I want to gain weight... that's what she said... what! lol something that is not very common amongst the female population.
Caloric Intake
Energy balance is the primary dietary driver of body weight and it also impacts body composition. A chronic surplus of calories will result in increased body weight and a chronic deficit of calories will result in a loss of body weight.
In other words, in order to gain about one pound of tissue weight (as opposed to transient flux in water weight), you need to consume a total of about 3,500 calories more than you expend. And to lose about one pound of tissue weight, you have to do the opposite -- consume about 3,500 calories less than you expend.
Thus, the first step in constructing any rational diet is to get a sense of how many calories per day, on average, you should consume in order to progress towards your goals.
The average number of calories you expend per day -- called total daily energy expenditure (TDEE) -- is a function of your basal metabolic rate (BMR) and your average weekly activity level.
To estimate your BMR, it's important to have a sense of how much lean body mass (LBM) you carry. If you're not sure, post a photo or two and we can estimate your percentage body fat and, from this number and your total body weight, it's easy to estimate LBM by using the following formula:
LBM = body weight * (1 - percentage body fat)
To estimate BMR, use the the Katch-McArdle formula:
BMR = 370 + (9.8 * LBM in pounds)
or
BMR = 370 + (21.6 * LBM in kg)
The next step is to estimate average weekly activity using the following guidelines to calculate an activity factor (AF):
• 1.1 - 1.2 = Sedentary (desk job, and little formal exercise, this will be most of you students)
• 1.3 - 1.4 = Lightly Active (light daily activity and light exercise 1-3 days a week)
• 1.5 - 1.6 = Moderately Active (moderately daily Activity & moderate exercise 3-5 days a week)
• 1.7 - 1.8 = Very Active (physically demanding lifestyle & hard exercise 6-7 days a week)
• 1.9 - 2.2 = Extremely Active (athletes in endurance training or very hard physical job)
To estimate TDEE (the calories at which you will neither gain nor lose tissue weight), use the following formula:
TDEE = BMR * AF
Now that you've estimated your TDEE, it's important to refine that estimate empirically. To do so, consume an average amount of calories equal to estimated TDEE for two weeks, monitoring weight change. The results will confirm your actual TDEE.
Once you know your actually TDEE, set your caloric intake to match your goals as follows:
To maintain weight, consume an amount of calories equal to TDEE.
To lose weight, consume 10% to 20% less than TDEE.
To gain weight, consume 10% 20 20% more than TDEE.
Monitor weight change via the scale and also body composition via the mirror and how clothing fits, making adjustments as needed biweekly.
Macronutrient Intake
Protein: ~0.6 to ~0.8 grams per pound of bodyweight -- the highest amount justified by research.
Fat: ~0.45 grams per pound of bodyweight -- the lowest amount implied by clinical observation.
Remaining caloric budget: whatever mix of macronutrients you prefer -- as implied by research.
