Can you be obese, but healthy? The short answer is really no. Think about it, obesity itself is an illness so right there you already have an illness, even if you're not necessarily on medications. Obesity means that your BMI or your body mass index is 30 or greater and just by having excess fat storage in your body puts you at a higher risk of developing other comorbidities or illnesses that go along with being overweight.
Also, walking around with 100 pounds plus or minus extra weight on your back, puts your heart and lungs at such excess strain. We know that patients who are obese, even if they currently aren't necessarily on any other medications, they already are at a risk of premature death. So please, if you are obese or even overweight, try to do something about it. Make some lifestyle changes. Talk to your doctor so that you can reverse some of these risks and live a happier, healthier, longer life.