While doing Starting Strength, don't worry so much about you look. Just concentrate on adding weight to the bar. The muscle mass and bone density gained will stay with you for a long time, with all kinds of health benefits (improved immune system, more resistance to injury, etc). Anyway, it's a short term program. Most people only do it about 3-9 months.
For nutrition, your main focus should be eating enough to keep making progress. If you're about 20% bodyfat, you probably don't need to pig out. Get lots of protein, get enough carbs to fuel your workouts, and eat enough good fats to feel satisfied. If you can keep getting stronger at 215, do that. If you need to slowly add weight to keep getting stronger, then do that instead.
Just to emphasize this, Starting Strength is temporary. Once you're done, you'll be much stronger than when you started and can do whatever you want afterwards. Whether it's losing fat, adding more strength, or something different, only you can decide.
Keep adding weight to the bar and good luck!
In matters of style, swim with the current. In matters of principle, stand like a rock.
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