This depends on intention and cultural norms. If fruit is a dessert in your culture, then it would not be permissible. If fruit is just a part of the meal and is eaten last among the different parts of the meal, then yes. Some parts are more challenging than others depending on what part of the world men are from. Cold showers are harder in Northern Canada than in Southern India. Desserts may be harder in some European countries than in Asian ones. Culture and climate all play factors.
Can I eat fruit between meals? During this exercise you have the opportunity to abstain from food between meals regardless of kind (unless, of course, one has specific health problems that requires more constant nutrition).
Do your best to embrace the disciplines as you can right where you are. The Lord will lead you if you ask him.
Can I drink juice? The organic sticker might tell us something about the juice, but it doesn't tell us whether or not it is sweet. I presume God smiled when he made oranges, apples, grapes, mangoes, and even bigger when he made pineapples. I think the Father likely said to the Son, "Man, these are some of the sweetest things ever made." Even if the juice doesn't have added sweeteners, if it is naturally sweet, it is a sweet drink. Thanks be to God for that. Let's offer them up in these 90 days.
Blessings on your Exodus.