Hello and welcome to the forum. Thanks for your question and we'll try to help. Have you seen your doctor to discuss this? That would be a terrific idea to pursue as they can give you true medical care and help. Here is some general information on varicose veins https://www.mayoclinic.org/diseases-conditions/varicose-veins/symptoms-causes/syc-20350643. Basically, weak or damaged valves lead to varicose veins. Being obese is a risk factor and losing weight would likely help a multitude of things in your life. That's never easy but something that would be very beneficial to work on. Sitting for prolonged periods of time also contribute to varicose veins. You are a young man and this should be a priority for your health. Eating a healthy diet and regular exercise if cleared to do so by your doctor could greatly change this situation as well as other health issues that are linked to our weight. Your doctor may have you elevate your legs more, wear compression stockings or perform a procedure on the veins. But ultimately, prevention involves weight management, exercise, eating a high fiber and low sodium diet, etc.
We have a great weight loss and dieting forum here https://www.medhelp.org/posts/Weight-Loss--Dieting/New-study--Calorie-Restriction-for-Better-Health/show/3047265 We
hope you get active in that group!