It's not about the food
Food - meals, together time, etc. - are the universal element in families... so when the balance is upset unilaterally (your diet) there will be conflict.
If there are underlying (read unresolved) conflicts (and trust me, as a fat child there are CONFLICTS about what is said, how you are treated.... EVERYTHING) then these will surface. But again, it's not about the food.
Only you can change your life. Be nice to your father. Eat those things which will help you with your goal.
You haven't stated your age, but that is important to know, as these conflicts play out a lot differently at 14 than, say, 30 or 45 years of age.
good luck. Stay strong.