For another perspective, your left ventricle enlargement may be secondary to the enlargement of the aorta root that causes regurgitation (leaking) of the aorta valve and the left ventricle compensates by enlarging and increasing compliance.
What is the size of the aorta root, left ventricle chamber size, heart wall dimensions? Was it an EKG that showed LVH? Was there an echocardiogram? Appropriate treatment and prognosis would depend on the parameters of the variables.
Aortic root may enlarged and growing and this condition can be corrected with a valve repair or replacement, and a probability that could reverse remodeling of the LV, etc. There may be other favorable scenarios...but need more information. If condition is from muscle disease the outcome may be as grendslori states, but there is a possiblity of stem cell in the future that can effectivle treat that condition.
Hypertrophic Cardiomyopathy (HCM) is a progressive muscle disease of the heart and there is no cure for any muscle disease. There are drugs that you can take to help relax the heart muscle so that it will allow the heart chambers to fill better. A Myoectomy surgery can also be done if there is an obstuction to the outflow tracts (HOCM). There is nothing you can do to slow down or reverse this disease. If diagnosed in adulthood, people can live several years, if diagnosed during childhood the prognosis is not as good due to the fact that a child is still growing, so are their heart walls. Children tend to go into diastolic heart failure when they hit their teen years, due to that growth. As far as eating healthy, everyone should be doing that anyway, but eating healthy isn't going to affect the HCM, or reverse it, in any way.