Answer:
sedentario: activo 
con cafeína: descafeinado
fuerte: débil 
adelgazar: engordar 
comer en exceso: estar a dieta 
con estrés: tranquilo 
sufrir muchas presiones: aliviar la tensión
fuera (out) de forma: estar en buena forma
Step-by-step explanation:
Opposites are as important in Spanish as they are in English. They are called antónimos (antonyms), meaning the opposite of a word. 
Learning antonyms allows us to connect associate connected words and therefore expanding our vocabulary. 
Some opposites are adjectives, such as "fuerte / débil", and others are verbs, such as "adelgazar / engordar".