Why do people that develop cancer ( especiallu colorectal) usually lose alot of weight, and very fatigued?

Answer 1

There are different reasons, but one of the primary reasons is that the tumors are a part of the human body. Sometimes they even develop their own blood supply. What happens is that the tumors are very demanding and taxing on the normal body functions. The body feeds the tumor, just like it feeds all organs within the body. Our body does not recognize cancer as something that's not suppose to be there. Which is another reason it is so difficult to get rid of it.

The result of the body feeding the tumor(s) is loss of normal body weight and fatigue. The tumors not only thrive on and take the body's nutrition, it saps the body of energy too. Our bodies mistaken cancer tumors as just another organ(s) that needs nutrition and energy to thrive.

Answer 2

Anything that has to do with the digestive tract, is going to make you NOT want to EAT....cuz what you eat, you have to poop out.
Usually it hurts. Thus the wieght loss, lack of eating and a lot of going to the bathroom is exhausting!!!!

Also, people with cancer are told to eliminate all animal fat from their diets........So, they are lacking in protein. thus making them more fragile, and fatigued.

Cancer is the "new normal" for you friend.

I only have Ulceative Colitis........which means if I eat, I go to the toilet 3-12 times a day, and it's very painful.

Cancer drugs, and treatments are not fun, and very depressing.

there are many complex answers to your question.

Depression
Fear of Eating due to having to Eliminate the food thru the colon.
Drugs they are on for treatment.
Diet Restrictions
Dieting to extremes to be healthier-- my dad did that. it was insane!

Answer 3

Because there digestive system is effected. The cancer robs the body of the nutrients, and your body becomes very tired because it's not getting what it needs to carry on. Which in turn robs your fat cells of their stored fat to try to make up for the nutrients lost.