The MD I was working with argued that I could have seen a impact on weight loss if taking a more extreme approach to dieting (basically an extremely high protein, moderate fat, moderate carb diet with 300-400 calories of intake every ~4 hours from sunrise to sunset) in conjunction with the metformin, but that approach didn't really fit my lifestyle at the time. If done correctly, this ostensibly maximizes the gluconeogenesis inhibition effect of metformin in conjunction with minimizing fatty acid synthesis by keeping blood levels at a consistent glucose deficit (thus encouraging lipolysis). I was also unconvinced that this isn't a just-so story, and thus I preferred to take a traditional 'keto' diet route (which has a lot more evidence backing it).