The number of calories you burn while walking will depend on your weight and how fast you walk. The more you weigh, the more calories you will burn. Walking faster also increases the caloric burn.

The number of calories you need to maintain a body weight of 145 pounds depends on your age, your height and how active you are on a regular basis. To lose weight, you need to take in fewer calories than it takes to maintain your weight.

Energy expenditure concerns calories burned versus calories consumed. Imbalances between the two determine weight loss, gain or maintenance. Bodies that store too much energy become overweight. One component of your expenditure is basal metabolic rate -- the energy you burn when inactive.

A 50-20-30 diet plan is based on the acceptable macronutrient distribution rate of carbohydrates, fats and proteins in your diet. On a 50-20-30 diet, 50 percent of your calories comes from carbohydrates, 20 percent from fats and 30 percent from proteins.

Water is both the most abundant nutrient on Earth and in the human body. The world has about 333 million cubic miles of water, according to the U.S. Geological Survey, or USGS, and the human body is about 60 percent water. The United States withdraws about 410,000 million gallons, or Mgal, of water per day.

The number of calories you burn in one hour of exercise depends upon several factors. The more you weight, the greater the exercise intensity and the longer the duration, the more calories you burn.

How many calories a 19-year-old should eat daily depends on size, goals, activity level and gender. Active males looking to build muscle need a lot more calories than petite women who are primarily sedentary.

Although it’s possible to lose 4 pounds per week by severely restricting your calorie intake, boosting exercise or combining these two methods for rapid weight loss, medical supervision is a must if you attempt to lose more than 2 pounds weekly.

Circuit training provides the benefits of cardiovascular training and strength training, burning more calories per hour than traditional weightlifting.

Walking is one of the best ways to jump-start your weight loss journey: It's low-impact and literally as simple as putting one foot in front of the other. If you walk at a 4-mph pace, you can consistently complete 15-minute miles.

Cutting calories is an effective way to lose weight fast, even if you don’t exercise as much as you know you should. The USDA offers weight loss guidelines in its 2010 Dietary Guidelines for Americans report. This comprehensive report suggests limiting intake of sugar, salt and saturated fats.

Fruits and vegetables, according to the Centers for Disease Control and Prevention, contain essential vitamins and minerals that can help to protect you from chronic diseases. Substituting fruits for higher calorie foods can also help you lose weight. Replacing your dinner with fresh fruits is simpler than it sounds.