Rice and almonds appear wasteful when measured by mass produced per unit of water used, but that's not a particularly useful measure for food. More useful is calories per unit of water and protein per unit of water.

Rice measured by calories per unit of water is more efficient than lettuce, celery, tomatoes, spinach, cauliflower, lemons, raspberries, peaches, and broccoli. It's less efficient than carrots and strawberries.

National Geographic has a nice interactive display of the efficiency of various crops as measured by three factors (water/weight, water/calories, and water/protein) here: http://news.nationalgeographic.com/2015/05/150508-which-cali...