Body Mass Index
The National Heart, Lung and Blood Institute uses the body mass index (BMI) to calculate a healthy weight based on height. According to the NHLBI BMI tables, a 5-foot 11-inch tall male should weigh from 136 to 179 pounds to maintain a healthy weight. Anything above or below this range would be considered overweight or underweight respectively.
Limitations of BMI
The NHLBI admits certain limitations to BMI calculations. It acknowledges that BMI "may overestimate body fat in athletes and others who have a muscular build" and "underestimate body fat in older persons and others who have lost muscle." As of 2010, there are some studies that suggest people classified as "overweight" on the BMI scale may actually be healthier and live longer than those within the recommended range.
Although BMI may give some indication as to what constitutes a healthy weight for a 5-foot 11-inch tall male, there are drawbacks and limitations to relying on that as a sole source of data. You should consult your healthcare provider to help determine your own ideal weight.