In the midst of a series on exercise, I shall, in this article, shift gears to discuss the appropriate diet when one is exercising regularly - a recurrent question asked by many.
It goes without saying that the calorie and nutrient requirement varies from sedentary individuals to athletes.
Let us begin with the question of optimum calorie requirements. There are standard calculations for normal adults, depending on age, lean mass, and body structure. Calories are added for different activity levels, based on the stress of the activity and the frequency. Using these, it is easy to arrive at a figure. The difficult part, however, is to stick to it. It is notoriously challenging to estimate burnt calories while exercising, or those consumed while eating.
A more objective measure is to assess the physical response:
We shall discuss these next week.
The calories needed are based on one’s body weight, exercise schedule and the need to gain/lose/maintain body weight. To calculate the daily requirement, we shall study two components:
Basal Metabolic Rate (BMR)
BMR can be calculated most accurately using the Harris-Benedict equation:
Males: 66.5 + (13.75 X W) + (5.003 X H) - (6.775 X A)
Females: 65.1 + (9.563 X W) + (1.850 X H) - (4.676 X A)
where, W is weight in kg, H is the height in cm, and A is age in years.
However, if it sounds too formidable, we can use simpler equations:
Males: BMR = Weight in pounds X 11 (1 kg = 2.2 pounds-lbs)
Females: BMR = Weight in pounds X 10
If you have access to a body composition machine, or can make the effort to calculate your lean mass, (details later) the equation changes to:
Males: Lean mass in lbs X 12.5
Females: Lean mass in lbs X 11
Energy Spent on Exercise
The calories burnt while exercising can be calculated depending upon the time spent on an exercise and how strenuous it is - mild, moderate or severe. Various calculators are available online or as apps (HealthifyMe, Cronometer are two such apps) which can guide you regarding the calorie content of foods consumed and the caloric expense of different exercises.
Note that we are here ignoring the calories burnt during NEAT and EPOC (discussed earlier), and also the differential effects of different foods (proteins and fats consume more calories in their digestion than carbs), which are harder to calculate. For practical purposes, it's best to see how the body responds to the schedule. If the set goals are being met, continue with the schedule. However, if one is gaining fat, reduce the total calorie intake, and if one is losing muscle, increase the calorie intake.
The macronutrient requirements come next. Good quality protein is important during exercise. For low to moderate exercise levels 1-1.5 g/kg daily, while heavy trainees need 2 g/kg or more, depending upon their goals (these people are generally professionals, and should seek specific guidance). This means that most exercising adults would do well to consume at least 100 g of good quality protein daily.
Good sources of proteins are eggs, meats, nuts, seeds, milk and milk products, legumes, etc. Serious athletes who cannot complete their protein quota, can consider whey or albumin protein powders, keeping in mind the extra expense involved.
Carbohydrates are tricky. If the aim is to lose fat, they should be curtailed to about 40% of the total calories consumed daily. If the aim is muscle/strength gain, higher consumption is desirable, especially on the day of a heavy workout. Whole grains and complex carbs are to be preferred over refined carbs and added sugars.
Fats are used to complete the quota of calories that remain. Fat consumption (as long as it isn't fried foods) doesn’t directly correlate with body fat gain across a vast range, and healthy fats should be part of everyone’s diet. These have been discussed earlier.
As an example, a 30-year female with weight 55 kg, who wishes to maintain weight but increase her fitness levels will need 1,210 cal as BMR, say 300 cal for exercise requirements - depending upon the level of exercise, and an extra meal pre or post-workout which we don’t count (to cover up for NEAT and EPOC). This means about 1,500 to 1,600 cal daily and one extra meal on the day of the workout.
A 35 year male weighing 80 kg, aiming to lose fat and gain some muscle will need 1,900 calories as BMR, say 300-500 cal for exercise and an extra meal on the day of workout, minus say 200-300 cal for fat loss. This comes to about 2,200 cal per day and an extra workout meal.
The caloric content of nutrients is as follows: proteins and carbs 4 cal/g and fats 9 cal/g. So, we keep 400-500 calories for proteins as a start. The carbs can be 40-60% of total calories as required, based upon your goals as discussed above. The rest is consumed as healthy fats. For strenuous exercise, it's good to consume a lot of fruits and vegetables daily, and consideration can be given to taking some multi-vitamin supplements in addition.
What is more important is getting weekly measurements of total weight and ideally lean mass, using Bodpod machines or body fat measurements with callipers, to judge the response to the schedule. If it is going in the desired direction, the same can be continued and assessed weekly. If not, calories can be increased or decreased as per requirements. However, there is no need to be obsessive about these measurements, as occasional “cheat meals” and missed workouts tend to balance out if one exercises regularly and watches one’s measurements weekly.
We shall discuss more about tailoring diet according to one’s goals next week. Stay tuned.
This is a recurring column published every Sunday under the title: A Guide to Exercise.
[Listen in to understand some broad thumbrules around good Nutrition and Fitness from Dr Chopra.]
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