The ideal diet for pet iguanas is a vegetarian one mixed in specific proportions. The easiest way to prepare it is to mix the vegetables in a blender or food processor. Because it's virtually impossible to overfeed an iguana, set out a shallow bowl filled with some of the mixture, and fill it when it is empty. Vegetables should make up roughly 75 percent of an iguana's diet; the rest comes from fruits (five to 10 percent) and grain-based fiber (15 to 20 percent).
Vegetables with Calcium
Half of the vegetables an iguana gets should be calcium-rich. For each mix, add at least two or three vegetables from a group that includes spinach, collards, beet greens, kale, turnip greens, escarole, alfalfa pellets, Swiss chard, dandelions and bok choy. Any mix of these will keep the proper calcium-to-phosphorus ratio in the iguana's body. All of the vegetables need to be chopped or shredded before they're blended.
Any combination of two more vegetables should make up the rest of the overall food mixture. Squash, broccoli, okra, sprouts, zucchini, carrot, bell pepper, beans, yams, or peas are all solid options.
According to greenigsociety.org, these vegetables add different nutrients or elements to an iguana diet. Squash, zucchini and okra provide fiber. Broccoli and carrots provide oxalates, while beans, peas and yams provide protein. Bell peppers add some color and, most importantly to the iguana, some extra taste.
Some iguanas will need additional supplements with the vegetable mix for a balanced diet. For most, this will require one powdered calcium carbonate or calcium gluconate (minerals) mixed with powdered vitamins A, D, E and/or K. Mix one part vitamin(s) with two parts minerals, and add to the mixture in the blender. For hatchlings, add a dash or small pinch to each feeding. For older iguanas, add a full pinch for every 2 lbs of weight, two times a week. Adult females may need a full pinch every feeding between December and the time they lay eggs. Before committing to a long-term regimen for your pet, though, you will want to consult with your veterinarian.
Some animal care professionals recommend a ratio of one part animal protein to two parts of vegetables for young iguanas. One site, the Silver City Serpentarium, suggests animal proteins like cooked chicken, crickets, water-packed tuna, eggs (scrambled or hard-boiled), meal worms, and even dog food. However, iguana's in the wild are "folivores," meaning they're committed vegetarians. Vegetables will give a pet iguana enough protein if you follow the blend recommendations.
The greenigsociety website notes that some vegetables should only be fed to iguanas on a regular basis, some as a occasional, as in a few times a month treat, and some rarely or never. The regular list includes acorn squash, alfalfa, collard greens and green beans. The occasional list includes cucumber, carrots, celery and cabbage. The rarely or never list includes lettuce, due to poor overall nutritional value, and corn, which is too low in calcium.