I am confident Brady believes what he says and honestly wants to help people. Whether what is in that book will be more helpful than some other books is debatable but there is no malice behind it. Also while a high priced book from what I understand of what it would ask you to do (which are not cheap changes) the price of the book is a non issue.
For people like me that need to live within reasonable means just eat lots of fruits, veggies, lean protein when possible. Easy on the grain and dairy when possible. If it is processed food even if supposedly healthy natural is probably better but I don't believe all processed food is automatically bad either.
My 5 rules for staying health and longevity are as follows.
#1 Eat healthy as stated above as much as possible
#2 Eat less than you need to. Lots of longevity research indicates less calories is better. Not crazy but if they say you should have 2500 a day for instance try to average 2000 and see how you feel. Frankly research suggest you should eat even less than that.
#3 Fast on occasion but no more than 7 days IMO. If for any reason it starts to feel weird stop (look more into fasting and health benefits for occasional short term ones). Also ties into #2 but a bit different. Talk to your doctor before you do it if you have health issues or concerns. Do your own research as well.
#4 Work out but not too hard. 2-3 hours of cardio a week is all you need. strength building using your own body weight (maybe a bit more) is all you need. I have read studies when people who push themselves too hard (run marathons or weight lift big or play pro sports) die earlier than average. I think there is logic to staying in shape but not asking your body to do unnatural things. You might be wearing it out more than helping it if you push it too hard.
#5 Use common sense and reason. Don't smoke, drink rarely, stay away from drugs (even over the counter unless you really need it). Also when it comes to prescription drugs I would say you should listen to doctors but generally get as many unnatural things out of your body as possible. If you don't need it don't take it. Weed if used should be rare as filling your lungs with smoke probably isn't a good thing I would assume so i don't do it really. Keep open to other new research but don't try to jump on every trend diet or health kick.