Several factors determine ideal weight. While it’s natural to gain some weight as we age, the most important factors are actually height, body frame and gender. Taller people should weigh more than shorter people should, generally 2 to 4 lb. per inch in height difference. For example, a woman who is 5 feet 5 inches tall and weighs 130 lb. will likely be proportionate to a woman who is 5 feet 8 inches tall and 140 lb. People, especially women, tend to gain fat over the years, but until you're around 40 years old, your age doesn’t play a big factor in determining your ideal weight. Knowing your ideal weight can help you to maintain a healthy lifestyle. Being overweight or underweight can have adverse effects on your heart, bones and muscles.
Weigh and measure yourself. Once you know your exact height and weight, refer to a weight chart. A woman who is 5 feet 6 inches tall and between 26 and 59 years old should ideally weigh between 136 and 164 lb. The standard weight for a man who stands at 5 feet 9 inches is between 142 and 176 lb. For each inch you are shorter, subtract around 3 lb. from both ends of the range; for each inch you are taller, add 3 lb. Weight calculators and health websites will help you narrow these numbers down even more. The Centers for Disease Control has weight assessments on its website (see Reference section).
Determine your frame size by measuring your wrist. The smaller the diameter, the smaller your bones are. Smaller bones are usually less dense and therefore lighter. Consider your frame size because it can affect your measurements; a person with a large frame might mistakenly think she’s overweight. For an approximate idea, if you wrap your thumb and index finger around your opposite wrist, you can estimate your frame size. If your fingers overlap, you have a small frame; if they barely touch, you have a medium frame; if they don't touch, you have a large frame.
Compare your weight with your age group. Age becomes a factor with weight because with age comes a slowed metabolism, and caloric requirements drop. If a 26-year-old man is used to eating 2,200 calories a day and continues to do so for the next 20 years, he will gain weight.
Talk to your doctor about your ideal weight. He will be able to provide a more precise depiction of your overall health. He can also help you take steps to increase or decrease your weight as necessary to make sure you stay healthy.