Fab trendy diets or eating for your blood type diet whats the secret?

In this day in age, we have all became so obsessed with diets and eating right but it never dawned on me till now we've been trying the wrong diets. One day I and my fiance was just watching TV and he came out randomly and said " You ever wonder why couples who been together for a long time bodies change at diff rates? They eat the same foods sometimes more or fewer proportions than the other but one ends up having high blood pressure or diabetes etc? One gets very heavy in weight and the other spouse may get lean or stay the same?" I said to him how I imagine family genetics and hereditary symptoms run in family's and some people catch it early or later on. He looked at me and said" You ever thought about eating for your blood type? " and shockingly I  responded no because I don't even know my blood type.They told me my blood type after my first pregnancy in 2015 but other than that I never paid attention or wondered about blood type.He said he recalled listening to a radio host by the name of Heather B a short time ago who he recalled her talking about the importance of eating for your blood type. 
Never hearing this conversation in my life or even considering my blood type would matter so much, this is the deepest, makes the most since topic that can be the true fountain of youth of our existence. When you go to the doctors we are observed as obese or underweight by a weight and height chart from years ago. When they ask us about our family health history we write it down and that's that. There was never a time my blood type was brought up to me why I  experience what I experience after them asking me what all do I eat.  So now that I've come across this topic  I wonder has anyone tried these blood type diets and how did their bodies react to it. Knowing this I'm so curious to do some research and take control of my health the right way but I'm currently 21 weeks pregnant So my adventure would have to start when I'm all healed and ready to workout.Us not knowing our blood type could be why our health can be bad at one point from feeding ourselves harmful things then good because we are eating the right things. Can knowing the right foods for our bodies save us from cancer, tumors, fibroid, inflamed hearts, arthritis etc? I never was a fan of medicine so if this new discovery helps I'm all for it, what about you?

                                        

Diet picture from source :  {https://i.ytimg.com/vi/YPl0naO6GR0/maxresdefault.jpg }