You wouldn’t dream of beginning a trip without first knowing your starting point. A weight loss journey is the same. You must know how many calories you currently consume before you can calculate how many you need to cut to lose weight. That means keeping a food journal. Write down everything you eat, how much, and when for at least two week days and one weekend day (people tend to eat differently on weekends). Tally the calories to find your starting point.

Another calculation method suggests that women between the ages of 18- and 30-years-old multiply their weight by 6.1 and add 487 for their basic calorie needs. (Women 31- to 60-years-old should multiply their weights by 4 and add 829.) Next multiply this basic number by 1.3, 1.5, 1.6, or 1.9, depending on whether you are sedentary, slightly active, moderately active, or very active, respectively. Once you have determined your current calorie intake, cut 500 calories from this total (or add 500 calories in exercise) to lose about a pound a week (3,500 calories = 1 pound.)

Or, there is an even easier formula. Try Dr. John Foreyt’s 100/100 Plan. To lose a couple of pounds a month, cut 100 calories from your daily diet and add 100 calories in exercise. This is as easy as eliminating the pat of butter on a slice of toast and walking 20 minutes every day.