Yes. Pistachios posses a relatively high-caloric value (1-ounce serving equals 160 calories) and consumption in large quantities can cause you to gain weight. However, it may be interesting to note that optimum consumption of pistachios has various health benefits as well, one of which is weight loss. The presence of fiber and protein in these nuts keeps you satiated for long hours and prevents frequent hunger pangs, all the while supplying your body with essential minerals.