Hi Demarques. I totally agree with Karin! Your very first step MUST be to have the client cleared with their cardiologist and/or family physician, as well as to work with them in designing/developing a fitness plan that they accept and agree with. Working with a client with know heart disease requires that you start there in my opinion.
I am not sure whether you make reference to food or exercise with your question. It appears that you have a client who needs to lose weight.
Either way, because of the second half of your sentence, I would suggest you refer this question to the client’s cardiologist and adhere to his/her recommendations.