Joan Endyke: Calories are the key to weight loss

Joan Endyke

Obesity rates have doubled in the United States over 20 years because we are overeating in relation to our age and activity level.

Obesity is a major risk factor for heart disease, stroke, certain types of cancers and type II diabetes. One of the national health objectives for 2010 is to reduce obesity to 1980 levels of less than 15 percent. According to the Centers for Disease Control and Prevention, 32.7 percent of U.S. adults 20 years and older are classified as overweight, 34.3 percent are obese and 5.9 percent are extremely obese.

Obesity is defined as having a body mass index of 30 or higher. BMI is calculated by dividing your body weight in pounds by your height in inches twice and then multiplying by 703. For example, the formula for a 200-pound, 5-foot-8 person would be: (200 divided by 68) divided by 68, times 703, equals 30.4.

Overweight is defined as a BMI 25-29.9, and extreme obesity is BMI of 40 or higher.

The CDC calls our society “obesogenic,” characterized by environments that promote overeating and physical inactivity.

People have the power to manage their weight, but first they must ask themselves: What is my calorie requirement? And how much am I actually eating?

Understanding calorie amounts is essential and can be empowering, enabling people to take control of their body and their health, picking and choosing a satisfying and enjoyable diet within a calorie budget.

Calorie needs decline with age and less activity. An active 18-year-old male requires, on average, 3,000 calories to maintain his weight. That same male man in his 30s, not exercising regularly, and working in a sit-down job, requires roughly 2,200 calories. Even with moderate exercise, he would require only 2,500 calories. If he keeps a similar eating pattern, he would gain 10 to 40 pounds annually.

Maintaining a strong, active lifestyle, with strength exercises, keeps calorie needs high, dipping only slightly with age.

Joan Endyke is a registered dietitian with a master’s degree in nutrition and food science, and a certified personal trainer. She is the nutrition director at Fitness Unlimited in Milton, Mass.