Today's diet blockbusters grace the pages of every magazine: Whole30, Paleo, Vegan, Ketogenic and more. Eating has suddenly become very confusing. Some diets advocate for whole grains and healthy carbs while others rail against it. Other diets say a high fat and high protein diet is the way to go. Which one is right? The truth is, you will adhere to the diet that fills you up adequately, gives you the most efficient energy and provides you proper nutrition for subsequent workouts. How do you know what you need?
One of the best methods for knowing how many calories to eat is to go to a sports medicine or athletic training facility and have your measurements taken. A DXA scan is the gold standard for your overall body fat percentage and your BMR—or Basal Metabolic Rate—will tell you how many calories you burn daily while at rest. There are also online calculators to help ballpark these figures.
Once you have that figure (let's say 1500 calories), you know you need to consume at least that amount to fuel your body on any given day at rest. Then, you can begin adding in the calories burned during workouts. For example, you do a bike workout that burns 500 calories and a run that burns 400 calories. That's 900 calories on top of the 1500 calories you should consume daily.
This is where the "what" you eat becomes important because no matter what way of eating you choose, you want it to include mostly whole, unprocessed foods with plenty of fruits and vegetables. It has been said you can't train your way out of a bad diet, and this is true. Believe me, I've tried to fuel my fair share of long runs on margaritas and tortilla chips since they were within my caloric budget. It doesn't work.