This avocado smoothie is sweet and delicious, and filled with fat burning and metabolism boosting ingredients. It's just 253 calories, and if you want to add a boost of protein, try adding a scoop or two of vanilla protein powder, or collagen powder.Special Tip: Avocados are high in fat, but these are healthy fats. And they actually tell your body to shed fat (because storage is not needed) so don't be put off but the nutrition label. This is a great weight loss smoothie.