Calories, Diet and Nutrition

What are Calories

Calories are units of energy and are used to measure how much energy there is in foods and drinks. One may find that calories are sometimes referred to as kcal (kilocalories). These are also known as the small calorie units and are mostly used in science. In nutrition, the term Calorie (with the capital "C") is used, and is also known as the large or food calorie. While the large calorie unit is in reference to Kilograms, the small calorie unit (in kcal) is in reference to grams, and so 1 Calorie = 1000 calories or 1 kilocalorie. In other words, a Calorie and kilocalorie refers to the same amount of energy, and so the numbers are interchangeable. When we eat or drink more calories than we burn, the excess gets stored as body fat. On average a man needs around 2500kcal and a woman needs around 2000kcal a day to maintain a healthy body weight. These amounts may vary, and are dependent on metabolic rate, age, size, level of a person's daily activities, as well as other factors.

What are DRI, RDA, RDI, DV, AI, UL, EAR terms

DRI (Dietary Reference Intake) is a system of nutrition recommendations that specifies different nutrition needs dependent on age, gender, pregnancy and lactation, and contains various recommendations such as  RDA, AI, UL, EAR.  In some countries the DRV (Dietary Reference Values) systems are used, and comprises of  PRI, AR, AI, RI  or  EAR, RNI, LRNI, Safe Intake  recommendations.  RDI (Reference Daily Intake), RDA (Recommended Daily Allowances) and AI ( Adequate Intakes ), as part of the DRI recommendations, represent daily dietary intake levels that are sufficient to meet the nutrient requirements of healthy individuals. A table of differing RDA's can be seen here. For food labeling, the RDA recommendations contain too much information, and so the DV (Daily Values) recommendations exist as established values to be used for food nutrition facts labels. The DV reference is mostly similar to the RDA and AI recommendations.

What is BMR

BMR stands for Basal Metabolic Rate, and refers to the amount of energy an individual expends when at rest. It may sometimes be referred to as resting metabolic rate. The BMR number may be used to estimate a person's total daily caloric expenditure. For example, using the Harris-Bendict formula for an individual that is on average lightly active through out the day, the calculation would be BMR x 1.53, or for a moderately active individual, BMR x 1.76. This value then may be used as general guide as to how many Calories a person may need to consume per day to maintain their existing weight.

Food Labeling and Nutrition

Nutrition facts labels are provided as a guide and give information about the nutritional content of foods and drinks. The nutrition labeling usually shows the amount and a percentage value of DV (Daily Values) of a nutrient, per serving or a given amount, which relates to the recommended amount of that nutrient for an individual per day. The percentage values are based on the DV recommendations which are based on DRI. More information on how to read, and what Nutrition Facts food labels say about nutrients in foods, can be found here. Find out which nutrients to limit, which ones to get enough of and get a better understanding of the footnote on the bottom of the Nutrition Facts Label.