London broil, a steak dish, is made with top round. Although London broil is not as lean as chicken breast, it's lower in fat and calories than some other types of steak and can be enjoyed in moderation if you assess the nutrition facts.

A single serving of London broil (approximately four ounces) contains 140 calories. It would take about an hour of indoor walking for an average 160 pound person to burn off all of the calories in a serving of London broil.

A serving of London broil contains six grams of fat including 2.5 grams of saturated fat. Although fat is necessary for proper health, the USDA recommends limiting saturated fat intake to just 10 percent of your daily calories.

The main source of calories in London broil is protein. A four ounce serving of London broil contains 19 grams of protein. The average man should consume 56 grams of protein a day, while the average women should consume 46 grams of protein a day for optimal health.