Most Type 2 diabetics are overweight, but not all. Around 10% are normal weight and so the idea that losing weight will always improve diabetic control isn't always correct - it depends upon the person.
Many people on this forum have improved their Type 2 diabetes or made noticeable improvements by chang8ng what they eat without reducing calories, in fact I certainly seem to eat more calories now (in T2 remission for over 5yrs) than I did while I was pre-diabetic and eating a so-called healthy low fat diet.
It is carbohydrates digesting into glucose which are the main contributor to Type 2 diabetes and so reducing our intake of them (starches as well as sugars) usually makes a much bigger difference than medicines such as Metformin. In fact after I was diagnosed and found this forum I bought a Blood Glucose monitor (finger prick type) and was able to see the difference in my Blood Glucose for myself comparing after eating my usual low fat meals and eating a low carbohydrate (higher Protein and higher fat meal.
However, we are not all the same and so some people require medication and there is no shame in that. I was lucky that cutting my carbs down to under 40gms per day (between 20gms and 40gms) put me into remission with no need for any medication. I did lose some weight, but only enough to get back to the weight I was in my late 30's (having been slim all my life until I was persuaded to eat that low fat diet.
It may seem too good to be true to be able to eat as much fatty fish, fatty meat, cheese and eggs as I like yet not gain weight, but that's the way it is for me and around 50% of the others in this forum. It's eating too many carbohydrates that make us fatter, just like farmers fattening up livestock by feeding them carbs.
