TOPIC: Can the sentences be modified and make them better?

I heard someone ask another person to whom he was speaking to keep a secret.
He said 'Hey, let me tell you something secert; Mary eats weight losing pills to reduce weights.'
I sensed there are troubles in his sentences.
Can the sentences be modified and make them better?

Yes, there are a few of problems in this sentence. It could be revised as follows:
The person said," Hey, let me tell you A secret: Mary TAKES weight LOSS pills to LOSE WEIGHT."

or
The person said, " Hey, let me tell you A secret: Mary TAKES DIET pills to LOSE WEIGHT."

Please note that "tell you something secret" is possible, but it is not as common as " tell you a secret".