I had no idea! I had a salad with some walnuts on it--about 1/8 of a cup, so I looked them up to figure out how many unplanned calories I'd added. Turns out walnuts have almost 800 calories per cup!!! Thank goodness it was only a few! But it made me think of all the times when I wasn't dieting that I would sit at my desk and graze on peanuts out of the shell...AND they have over 800 calories a cup!! No wonder I gained so much weight!! (And I had NO idea the avocados I loved had like 400 calories each--I thought they were just high-fat, but healthy!)
Think of it this way....you aren't eating fried foods. Almonds ans walnuts are good for your heart. The calorie content is outrageous, but you use them in moderation. It is still a step in the right direction.