Complex sentence: Heather MacAllister (February 25,1968--February 13,2007) was an American performer and activist for social justice in a number of areas but was particularly active in the fat acceptance movement.
Split into simpler sentences: Heather MacAllister (February 25,1968--February 13,2007) was an American performer and activist. She was active in a number of areas but was particularly active in the fat acceptance movement.