We all love nuts, but we’re careful not to eat too many because of the high fat calories. Now, there may be less to worry about. In a series of studies, USDA’s Agricultural Research Service (ARS) physiologists David Baer and Janet Novotny looked at how many calories of almonds, walnuts, and pistachios are used by the human body. There are a lot of factors to consider, such as whether the nuts are raw, roasted, or ground, and how well they’re chewed.