His diet, as he described it: raw fish caught by hand in the open water around the boat; seabirds caught at night, when they landed on or near the boat to sleep; sea turtles, which he caught when they surfaced near the vessel; jellyfish; and whatever edible material he could scavenge from floating debris that drifted past.
For hydration: rainwater when squalls passed over, collected in every available container on the boat; turtle blood, which he used as a fluid source particularly during dry periods (a medium-sized turtle might yield approximately one liter of blood); and in extreme circumstances, his own urine. The experts who reviewed his survival strategy noted that drinking urine in small amounts during extreme dehydration has a limited but real utility — its salt content is lower than seawater, and it recycles some fluid — though it is not recommended as a survival technique and is ultimately counterproductive if used as a primary water source over time.
The metabolic picture, as the experts assembled it: Tipton noted that after the first day or two of food restriction, the body shifts into conservation mode, slowing metabolism and reducing caloric requirements. A resting adult needs approximately 1,000 to 1,500 calories per day under these conditions. Piantadosi noted that body fat and muscle can sustain a person for an extended period as long as the essential micronutrients, vitamins, and minimal protein are available. Alvarenga, as an experienced fisherman who understood his resources, was systematic enough in his food gathering to maintain a baseline supply of all of these.