Legumes are among the oldest cultivated food crops and remain among the most important sources of food worldwide. Peas, beans and lentils are all capable of long-term storage in almost any climate, while most other forms of high quality protein are notoriously perishable. Both beans and lentils are versatile and nutritious.
Lentils are thought to have been the first legumes cultivated and among the very first crops of any type. The plants are short, typically less than two feet in height and produce their seeds two at a time in small pods. There are many varieties grown around the world in a range of sizes and colors. In India and the Middle East, where lentils are a staple, they are considered to be especially digestible and accordingly are fed to invalids and small children. Lentil porridge is often the first solid food given to infants.
Beans are among the most numerous families of edible plants, with unique varieties originating in Europe, Asia, Africa and the Americas. Some varieties are consumed young as a vegetable while their pods are tender and juicy. The majority, however, are are eaten as mature seeds. Although many beans have a distinctive flavor, most share a characteristic savory note caused by enzymes breaking down their fatty acids into complex aromatic molecules.
All legumes share a common structure. The two meaty portions, called cotyledons, provide a nutritional storehouse for the embryonic plant inside. The tough protective skin is made up of insoluble fiber, necessary for the proper functioning of our digestive system. Legumes are uniformly high in protein, with most also containing significant quantities of starches and sugars. Legumes also have a variety of chemical defenses, which is why they are all but invariably eaten cooked. In most cases these chemicals simply interfere with the absorption of nutrients, but a few legumes are actually toxic when raw.
Lentils, because of their thin shape, will generally cook more quickly than beans. Dry beans require presoaking or long cooking because their skins are water-resistant and slow their absorption of cooking water. Some varieties are split and skinned, allowing them to cook as quickly as lentils. Beans are typically larger than lentils and most varieties produce more seeds per pod. Beans are especially high in indigestible sugars, which accounts for their flatulence-inducing reputation. Lentils do not have the same effect.