Serving vs. Portion Size

• Serving size does not necessarily equal portion size. Serving size is a term used on nutritional labels to help quantify calorie content. Portion size is the actual amount of food you eat. Portion size can be estimated by hand. Your fist approximates 1 cup, your palm 3 oz., thumb tip is 1 tsp., 1 whole thumb is about 1 oz.
  
  

Simplifying with Food Groups

• The seven major food groups are fruits, vegetables, grains, nuts and seeds, beans and legumes, dairy and meats. Many of the foods in each group fall under the same category of food type and density. Of course this is not a hard and fast rule, but it presents a reasonably reliable way to sort out and get a rough idea of calorie content based on group rather than trying to memorize the calorie specifications for a wide variety of specific foods if you don't have immediate access to nutritional facts.
  
  

Calories and Food Type

• Carbohydrates, proteins, fats, fiber and water are considered macronutrients. Our body requires macronutrients in large quantities. Generally a food will offer a mix of different macronutrients, but it will be dominant in one or two foods. That's why foods are often referred to as being protein, fat, carbohydrate or fiber rich. Food type is determined by the macronutrient the food is most abundant in. For example, meats, nuts and eggs are considered proteins. Cheese, butter and oils are considered fats. Fruits, vegetables and grains are considered carbohydrates. Just knowing what type of food your eating and the macronutrients it has to offer gives you some general information as to its calorie content. Proteins and carbohydrates each contain 4 calories per gram of that nutrient. Fat contains 9 calories per gram, alcohol contains 7 calories per gram and fiber and water each have 0.
  
  

Food Density

• Food density is based on the calorie potential of a food in relation to its weight. It's calculated by dividing the total number of calories in a food serving by the weight of that serving in grams. Low density foods fall between 0 and 1.5, moderately dense foods are between 1.5 and 3 and high density foods have a result greater 3. The lower a food's density, the fewer calories it offers in proportion to its weight. Most fresh fruits and veggies fall in the low density category. Most meats fall in the high density category. Familiarizing yourself with the density ranking of different foods provides you with another tool to estimate calorie content on sight.
  
  

Food Preparation

• Food preparation is another important factor to consider when estimating calories. Processed foods, with their food additives, generally have more calories than comparable sizes of fresh food. Frying a food adds a great number of calories because of the fat rich oil; while boiling or steaming a food adds no calories because water is calorie free. Consider the individual ingredients in the food. Don't just think pizza, for instance. Think bread, cheese, tomatoes... break it down.