Your friend Christine has been overweight for the past five years, mainly due to a sedentary lifestyle. She recently joined a fitness program and is finding it difficult to keep up with the rigorous...

Your friend Christine has been overweight for the past five years, mainly due to a sedentary lifestyle. She recently joined a fitness program and is finding it difficult to keep up with the rigorous activities laid out for her. What advise can you give her about her energy expenditure so that she can lose weight?