Many diners face a mystery of sorts at restaurants: They don't know how many calories are in the dishes they're eating. And when they guess, they greatly underestimate the numbers. So says David Zinczenko, author of the new book Eat This, Not That! written with Matt Goulding (Rodale, $19.95).

Generally speaking, to choose produce (fruits and vegetables) over processed food is a nutritional victory. For anyone who ever argues that, for example, carrots are high in calories it helps to know the relative numbers. This list of calories in 51 fruits, vegetables, peanuts and beans is compared to popular convenience foods.

A food’s fat content is important, but when it comes to weight loss, total calories are more important. So many of the low fat products on the market aren’t calorie reduced. Example, 2 tablespoon of reduced-fat peanut butter have the same number of calories as the regular kind. For effective weight loss, let’s explore some calorie-cutting tricks..

The problem of food calories has become extremely important and urgent nowadays. The ‘era of fast food and hot dogs’ couldn’t help influencing our tastes and as a result our weight. The number of overweighed people has grown in the course of time and as a result – thousands of people suffering from excess weight.

Combining of vegetarian foods isn’t necessary to get more than enough protein. Eating an adequate number of calories per day made up of any normal variety of plant foods gives us all the protein our bodies need.

Food energy is the amount of energy in food that is available through digestion. The values for food energy are expressed in kilocalories (kcal) and kilojoules (kJ).One food calorie is the amount of digestively available food energy (heat) that will raise the temperature of one kilogram of water one degree Celsius. Some advocate the convention of the capitalizing the C in these so that one Calorie is equal to 1000 lowercase calories, but that convention is not generally followed. The large Calorie is sometimes abbreviated kcal, to indicate clearly that is 1000 times as large as the small calorie formerly common in chemistry and physics usage. Consequently, the prefix kilo- is not used with large Calories. Food calories are also more specifically called kilocalories on the basis of the small calorie usage. This term, which makes it clear that large calories are intended, is widely used by professional nutritionists when speaking in terms of calories rather than joules, but the term kilocalorie for the large calorie is less often used by laypersons.The International System of Units unit kilojoule (kJ) is becoming more common. In some countries (Australia, for example) only the kilojoule is normally used. Some types of food contain more food energy per gram than others: fats and ethanol have particularly high values for food energy density: 9 and 7 kcal/g, respectively. Sugars and proteins have about 4 kcal/g. One (small) calorie is approximately equal to 4.1868 joules. One kcal is 4.1868 kJ.Each food item has a specific metabolizable energy intake (MEI). For a normal human this value is obtained by multiplying the number of kilocalories or kilojoules contained in a food item by 85%, which is the amount of energy actually obtained by a human after the digestive processes have been completed.