The Zimbabe Secondary School Science Project (ZIM-SCI) developed student study guides, corresponding teaching guides, and science kits for a low-cost science course which could be taught during the first 2 years of secondary school without the aid of qualified teachers and conventional laboratories. This ZIM-SCI study guide includes activities and experiments for a two-part unit in which students investigate: (1) the role of food as a fuel; (2) three major food groups (fats, carbohydrates, and proteins); (3) the use of food as a fuel in living things; (4) characteristics and reactions of carbohydrates; (5) digestion; (6) breathing; and (7) photosynthesis. Information is provided throughout the unit to help students understand the scientific concepts behind the activities and experiments. (JN)