This documentary was made for the purpose of illustrating how the fast food industry has no regard for nutrition and illustrates how it encourages poor nutrition for profit only.
So, some possible suggestions that are stronger:
- The fast food industry encourages poor nutrition by serving calorie-laden food.
- Fast food franchises' products are non-nutritious and addictive.
- People can become obese by eating too much fast food.
As you know, Mr. Spurlock actually DID become obese and his cholesterol shot up sky high after eating at a certain fast food chain. And, he only super-sized his meal when it was offered to him by an employee. It took him over a year to lose the weight he gained and get back to normal.
I think you need to revise you thesis because if you are writing about this documentary, the fast food industry was NOT presented as "something nice". Good luck!