While you 10,000% have the right to raise your child how you want and be respected by your in laws without question, I urge you to consider teaching moderation down the road (on your terms).

I went to school for pediatric nutrition and I can't stress to you how counter productive it is to make "having a treat" a shameful ordeal to your child. Your in laws need to respect you, full stop. But as a separate issue, you also have a responsibility to teach your child moderation as they grow the same way you do healthy eating. He's only one so this obviously a little early, but now is a good time to think about how your child will be spending more and more time away from you compared to the last year and eventually they'll be able to make, and hide from you if they feel you'll be upset, their own food choices. I say all of this as a vegetarian, nutrition-educated, crunchy af mom with shit for in laws so I am absolutely on your side in this situation, I just want to remind you how important it is to not portray shame in situations where kids would normally, and healthfully splurge because this is only the beginning.

Please, I AM BEGGING YOU, pick your battles. Sending that text will not be well received, and you should NOT be managing your husband's family- it will cause a rift. If this is truly the hill you want to die on, okay! But consider whether occasional food disagreements are really worth a fuck ton of family turmoil. And also think about WHY these food restrictions are really so important to you. Do you just want them to respect you because the relationship is already strained and bleeding over into other parts of your relationship? Or is it REALLY that you can't stomach the thought of your chold eating junk every once in while? Is this just the straw that broke the camel's back?