If you're on a tight budget to afford this year's latest kiting gear, you might also get some great benefit from keeping track of your calories so you don't spend any valuable gear money on unnecessary food. You can meet these calorie needs many different ways, but for those of us refreshing our quiver of race foils every year, a big sack of rice and jumbo pack of ground beef goes a long way to meeting these needs on a shoestring budget...
One of the most accurate formulas for calculating calorie needs is the Mifflin-St. Jeor Equation. This is the current method most nutritionists and dietitians use when consulting with patients and clients, it has been validated in a variety of published studies.
From Livestrong.com:
According to Nutrition Therapy and Pathophysiology, the Mifflin-St. Jeor equation was developed in 1990 and has been validated by more than 10 studies. The Mifflin-St. Jeor equation is gaining popularity among the nutrition professionals for accurately estimating caloric needs. The equation is as follows: for females = 10 x (Weight in kg) + 6.25 x (Height in cm) - 5 x age - 161; for males= 10 x (Weight in kg) + 6.25 x (Height in cm) - 5 x age + 5. These equations are also multiplied by the same physical activity factors* to estimate daily caloric needs.
So for my 75kg of "naked weight" I would use the formula thusly:
((10 x 75kg) + (6.25 x 175cm)-(5 x 31yrs old)+5) x 1.2 = 2032 calories per day...so for an average height/weight young-adult male, I need almost exactly the FDA recommended value of 2,000 calories per day to maintain my current body weight given my activity factor.
There's an easy to use calculator at this link that will allow you to use any units of measure as it automatically converts.
Once you calculate your calorie requirements, there are a lot of ways to track and manage your eating habits to hit your targets. I'm a fan of http://www.myfitnesspal.com because there's an easy to use cellphone app that allows me to keep a daily log of food and allows me to track Protein, Carbs, and Fat separately and also has a huge user-verified library of foods where people have input the calories and nutrient composition, so finding my favorite foods and logging them correctly is quick and easy. I'll cover nutrient ratios in a separate post, but being able to focus on a low car/high fat nutrient breakdown is how I lose weight while feeling good. Switching to a high carb/low fat diet allows me to put on weight and muscle while also having tons of energy for sports, so this is a very valuable feature for me.
* this is the physical activity factor cited elsewhere on the page I linked, 1.2 is for a sedentary lifestyle (I work an office job) 1.3 for a more active life and 1.4 for people who are active daily. If you're in doubt about which activity factor to use, pick the lower of 2 options, it will under-estimate your calorie needs and be a more conservative answer when it comes to weight loss or maintaining your current weight.