I know many "overweight" people who have type 2 diabetes.
Have a complete physical to determine if this is your problem. If so you'll have to watch those simple carbs.
Don't do any type of diet. Try eating "normally" (aka "healthy") and riding more miles to get the weight off.
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.