As a person who made a living* making smoothies for high-level athletes for the past 3 years, I am confident in my smoothie/shake-making abilities. When they think of smoothies and shakes, most people probably think of:
                  A.  a bodybuilding gym bro chugging water and protein powder in a shaker bottle
                 B. a health-obsessed yoga guru sipping on a green juice in her Instagram story

While we might be bombarded with these images on social media, there are actually shakes for all kinds of health goals - weight loss, weight gain, muscle gain, maintenance, etc. The key to a perfectly balanced smoothie or shake is to add ingredients that give you either macronutrients (protein, fat, carb) or vitamins and minerals and other good-for-you things.