TYPICAL SODA CAN LABELS

CONTENTS and NUTRITION

Typical Diet soda (left) and Regular soda (right)

NUTRITION

All packaged food sold in the U.S. have labels indicating not only ingredients but also nutritional values. Nutritional values include both caloric content and vitamins and minerals.

Calories involve simple thermochemistry. A Calorie is defined as the amount of heat needed to to raise the temperature of one kilogram of water 1 °C (from 14 -15 °C). It is equal to 4.18 Kj. This dietary Calorie is spelled with a capital C to distinguish it from a calorie which is defined as heating 1 g of water 1°C.

The three major classes of calorie providing foods are Fats, Protein and Carbohydrates.

Each of these can be metabolized or burned to CO₂ and H₂O giving off energy. The concept of State Functions in Thermodynamics means that it does not matter whether a gram of sugar is literally burned by lighting a match to it or metabolized in the body, the energy change is the same.

This energy can be used by the body for heat, moving or even thinking. If it is not currently needed, it can be stored as chemical energy. Long term storage of energy in the body is provided by fat.

• The following energy approximations hold:
  • One gram of protein furnishes....................... 4 Calories
  • One gram of Carbohydrate furnishes............. 4 Calories
  • One gram of Fat furnishes............................. 9 Calories

In theory, this means.... eating nine grams of carbohydrate or protein which is not currently needed by the body will give rise to the storage of four grams of fat.

© RWK 1997