Whether you are trying to lose 5 pounds or more than 50, the same simple laws of physics determine whether or not you will lose weight and how fast your weight loss will occur. Remembering these simple guidelines and putting them into practice can lead to weight loss without the aid of any special diet plans, books, or medications.
Our weight is determined by the amount of energy that we take in as food and the amount of energy we expend in the activities of our day.
Energy is measured in calories. If your weight remains constant, you are probably taking in the same amount of calories you burn each day. If you’re slowly gaining weight over time, it is likely that your caloric intake is greater than the number of calories you burn through your daily activities.
Everyone is in control of the amount of food he or she consumes each day, so our intake of calories is something we can control. To a major degree, we can also control our output of energy, or the number of calories we burn each day. The number of calories we burn each day is dependent upon our basal metabolic rate (BMR), the number of calories we burn per hour simply by being alive and maintaining body functions and our level of physical activity.
For some people, due to genetic (inherited) factors or other conditions, the resting metabolic rate (BMR) can be slightly higher or lower than average. Our weight also plays a role in determining how many calories we burn at rest — more calories are required to maintain your body in its present state, the greater your body weight. A 100-pound person requires less energy (food) to maintain body weight than a person who weighs 200 pounds.
Lifestyle and work habits partially determine how many calories we need each day. Someone whose job involves heavy physical labor will naturally burn more calories in a day than someone who sits at a desk most of the day (a sedentary job). For people who do not have jobs that require intense physical activity, exercise or increased physical activity can increase the number of calories burned.
As a rough estimate, an average woman 31-50 years of age who leads a sedentary lifestyle needs about 1,800 calories per day to maintain a normal weight. A man of the same age requires about 2,200 calories. Participating in a moderate level of physical activity (exercising three to five days per week) requires about 200 additional calories per day.
How do you “lose” weight?
The most effective method for weight loss is reducing the number of calories you consume while increasing the number of calories you burn through physical activity.
To lose 1 pound, you need an expenditure of approximately 3,500 calories. You can achieve this either by cutting back on your food intake, by increasing physical activity, or ideally, by doing both.
For example, if you consume 500 extra calories per day for one week without changing your activity level, you will gain 1 pound in weight (seven days multiplied by 500 calories equals 3,500 calories, or the number of calories resulting in a 1-pound weight gain). Likewise, if you eat 500 fewer calories each day for a week or burn 500 calories per day through exercise for one week, you will lose 1 pound.
Examples of calorie content of some popular foods and beverages include:
one slice original-style crust pepperoni pizza – 230 calories
one glass dry white wine – 160 calories
one can cola – 150 calories
one quarter-pound hamburger with cheese – 500 calories
one jumbo banana nut muffin – 580 calories
Any activities you do throughout the day are added to your BMR (basal metabolic rate) to determine the total number of calories you burn each day. For example, a 170-pound person who spends 45 minutes walking briskly will burn about 300 calories. The same time spent on housecleaning burns about 200 calories, and mowing the lawn for 45 minutes consumes around 275 calories. For more, please read the Calories Burned During Fitness Activities article.
How fast should you expect to lose weight?
Most experts agree that a safe, healthy rate of weight loss is one to 1 ½ pounds per week. Modification of eating habits along with regular exercise is the most effective way to lose weight over the long term. It is also the ideal way to ensure that the weight stays off.
Starvation diets may result in rapid weight loss, but this weight loss is almost impossible to maintain for most people. When food intake is severely restricted (below approximately 1,200 calories per day), the body begins to adapt to this state of poor nutrition by reducing its metabolic rate, potentially making it even more difficult to lose weight. It is also possible to experience hunger pangs, bouts of hypoglycemia, headaches, and mood changes from overly stringent dieting. These symptoms can result in binge eating and weight gain. Since a highly restrictive diet is almost impossible to maintain for a long time, people who attempt to starve themselves thin often start to gain weight again when they stop dieting.