I'm hoping you mean cutting meals as in having jacket potato and salad or something simple rather than going without as such?
OP what's purpose for you overpaying? Is it because the mortgage will be up for renewal shortly, your income will drop and you are trying to get the affordability down or reduce an LTV bracket.
Do you have other debt or any savings?
I am a huge advocate of overpaying the mortgage but you need to build a savings cushion first and make sure it is the debt which saves you the most money.
Having a clear goal is good. I want mine gone by the time the kids are at secondary school so I can afford nicer holidays etc. At the moment they absolutely love camping or a cheap caravan. We are still having holidays but they are very budget which at this stage is fine.
I've never bought take away coffee and I always take my own lunch. Buy very little in way of clothes and currently cut my own hair and the rest of family (bought a crea clip in lockdown and not been back but we have mad curls so quite forgiving!)
We are quite strict with food budget and I will stretch meals with lentils and veg to get two nights rather than one out of them but this has a health and convenience benefit too so don't really see it as a sacrifice.
I am quite careful with every penny, probably too much so at times!