Avocados have nearly 300 calories per fruit. A whole mango has only half that. On the lighter end of the spectrum, one cup of melon or berries has around 50 calories. Don’t give up the guacamole just yet. Avocadoes supply tons of essential fatty acids that are healthful and necessary. Like all things, though, enjoy them in moderation as a part of a nutrient-dense diet. Avocadoes can even be grown indoors and will fruit in the pot.