The ISS international partners agreed to base their diet plan on the recommendations of the World Health Organization (WHO). Please see https://drive.google.com/open?id=1B4_5Z22vjuFCJ1y3KO1WNg_-Ioe35_oG for a thorough discussion of nutrition in spaceflight. There has been little variation from this diet, except for the pro-K diet study completed by NASA recently. Basically, they follow a high carbohydrate diet of 50% carbs, 20-30% fats and 20-30% protein. The typical protein intake is a rather high 1.5 g/kg of body weight, as compared to the USRDA of 0.8 g/kg. The pro-K diet study described in https://drive.google.com/open?id=1MrqYix0oFK5dA0YIxIZ3qDvFmXqvK1y9 attempted to counter metabolic acidosis with high potassium-containing plant foods, but the results were limited. The conclusion of the investigators (Drs Scott M. Smith and Sara Zwart at JSC) was the effects of the diet were overwhelmed by the effective daily use of the Advanced Resistive Exercise Device (ARED). They did, however, expect the high K, low animal protein diet to limit bone and muscle tissue loss in the absence of use of the ARED.