Sorry, I disagree and won't be signing this.
How exactly would this work in the real world? Small businesses are already buckling under a weight of petty regulations and bye-laws.
What's your plan for how they arrive at the carb count? Do they just whip out Carbs & Cals, which is useful, but, as we all know, has limitations and sometimes needs to be taken with a pinch of salt?
Or do they need to send sample meals to a lab to be tested, at who knows what cost?
And then how do you know the meal served to you is the same as the test one sent to the lab?
Will local authorities be given the power to employ testers to do spot checks? Will this increase council tax?
Will there be civil liability if your sugars end up higher than expected even though a million and one other things can increase it besides an inaccurate menu carb listing?
Will you trust the carb count, or will you do what we all do anyway, which is make our own judgment calls over any meal? As that's normally the case, what's the point in forcing small businesses to comply with another rule?
By the way, it's important not to overstate your case. Your petition says that an extremely low blood sugar could lead to a sufferer going into a coma or dying. Sure, that could happen in extremis, but, erm, if I miscalc on a sit out meal, a few glucotabs sorts it. Dying? I've never really let it get that far. Even if your petition otherwise has merit, it loses credibility to suggest that we're facing death or coma because heartless small businesses inbetween negotiating supplies, overdrafts, staff rotas etc. etc. can't do a carb count as well.