Thanks for asking this question. Diabetes can be a big burden in someone’s life and it’s appreciated when others try to make things a bit easier.
Please do not be the sugar police.
You have two options, either:
- treat them as you would treat anyone else, or
- have a conversation with them at a neutral time when no food is involved*.
* although tread lightly as some people have unhealthy repressed emotions about their condition.
Please don’t bring something specifically for the individual without first discussing it with them. This singles them out, makes a whole lot of assumptions, and has a good chance of making them feel much worse than if they simply said “no thanks” to the cake. (But by all means bring an alternative option for everybody.)
- Unless they indicate otherwise, offer them what you are offering everyone else. With no hint of pushiness.
- “No thanks” means “no.”
- Don’t give them more than they ask for.
- Don’t say “just one won’t hurt.”
If they are using insulin, to avoid hospitalization, you must not:
- Intervene or shame them if they are eating something.
- Offer “diabetic anything” or “low/zero-sugar anything” without informing them.
Diabetes varies greatly from person to person. Different people will have different foods (and drinks) that set them off.
There are many ways of managing diabetes. Some people do their best to make their insulin match what they eat (which means that sometimes a carefully sized piece of cake or confectionery is ideal to stabilize their blood glucose trajectory). Other people try to take an approach of moderation. Others drastically reduce their carb intake. Others stick to a fixed routine. Others have received poor medical advice, so are confused and stressed and probably don’t want to be reminded about their condition.
You say cake is a problem “due to the sugar content”. This is a common misconception. Generally it’s carbs that are a problem. I have Type 1 diabetes and I have just as much trouble with white rice and wheat flakes, as I do with cake. Pizza is a problem, too (for more complex reasons). Ice cream and chocolate are much easier to deal with. As I said, these things vary between people.
Yes, some people would prefer to be be given a healthy alternative, or receive external motivation to make better choices. But don’t assume they do, and don’t assume you know what “better choices” means.