Re: 7 month old not gaining weight
Oz for oz, breastmilk has more calories than most solids. Therefore, my first line of defense would be to increase the number of times per day that your baby nurses, particularly if he is nursing less than the usual minimum for an exclusively breastfed baby, which is around 8x per day.
I would also focus on feeding baby high-calorie solids like avocado, meats, whole-milk yogurt, and beans, and adding some olive oil to his low-calorie fruits and veggies.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"