Is it unreasonable to be frustrated by a guest who says they eat anything when they actually don’t?

This! My late father was the sort of person who'd 'eat anything' - but by that he meant roast dinners, fish and chips, salads made from traditional salad vegetables with salad cream (even mayo was a new one on him!). Chickpea dishes, tacos and the like wouldn't feature anywhere on his list and that's OK. Might need to modify your meals when she's visiting.

I totally understand why you find this frustrating!

She is probably trying to be polite and not put you to additional expense. She probably thinks she does eat most things - because it doesn't occur to her that you will serve her things she hasn't come across - I guess she has no way of predicting this. If you have never heard of tacos, you can't imagine your response to being offered one.

Go through with her the meals you are planning to serve for the rest of her stay, and ask her to flag up anything she is concerned about? That's all you can do, really.

I can tell you are doing your best, and it must be a bit stressful.

Just spotted it. Do we have one from premier inn? To get all sides because Leonardo is quite... Pricey isn't it

https://weetabix.co.uk/bix-fix/great-british-breakfast/

Yogurt lacking there. I get it. I can't eat it in a morning. Love itany other time

I wouldn’t eat breakfast cereals at all.

Yes, and I would eat it for breakfast at a hotel. I wouldn’t buy it for my own home.

My mum is very adventurous and loves cooking and is also very well travelled and will always lean towards non British food. My in laws are definitely meat and 2 veg and have genuinely uttered the words, that's not for the likes of us, when offered a meal in a nice restaurant. I have other family members who once got offended that I cooked a free range chicken, as normal chicken is good enough for us.

Nowt to do with age. I do think class and big world experience does make a difference, however it's all horses for courses.

Even my husband would class his fave meal as sausage chips and beans and is constantly bewildered but all the saucy/wet food I serve up.

My mum and I go to all the nice restaurants together as they are wasted on him

61% of Brits said they would eat granola and yoghurt for breakfast - https://www.leonardohotels.co.uk/blog/great-british-breakfast-survey

Well you’re unusual to many of us. We eat either oats, granola (sugar free) or Bircher muesli most mornings. Other breakfast cereals aren’t very nutritious so there’s no point to me to have them. Same for flavoured yoghurt - we don’t eat them because they’re full of sugar we have Greek plain.

Granola is just a crunchier and often sweeter version of muesli, which has been a standard breakfast food since at least the 1970s.

Maybe they stock yoghurt for people to eat as a dessert-which is more traditional. If you went out and took a poll of the most common breakfast foods I don't think yoghurt and granola would be in the top 5.

I don’t think granola and yoghurt would be my first thought if I was laying in breakfast supplies - I’d get things for a fry up, eggs, or croissants, crumpets, nice bread for toast - but equally, I don’t think yoghurt and granola is a completely outlandish breakfast.

I make my own granola 😁
And Weetabix is vile. It turns into mush when you add milk. Isn't that why they give it to babies and people who require a soft diet?

Well your experience differs from mine and many others commenting. I’ve never even tried granola, I don’t think I know anyone who eats that for breakfast on a regular basis so I disagree that it has been a regular common breakfast item for many years! Also weetabix is definitely a normal cereal and has been for many years. My kids were definitely eating it 25+ years ago!

You not buying or eating it dosent make it something that only a small number of people do though. It is, and has been for a long time, standard breakfast food for a huge number of people. You can have any flavour of yogurt you like on granola.

It’s because she likes all the food people of her generation and friends eat

That is just not true. I don't think it is generational. She is only in her 60s. I won't see 60 again and I don't know anyone my age with such a limited diet. I agree with @oneoffname that it is a lived experience rather than age.

Just keep her food bland.

Somebody saying that people in the real world don’t eat yoghurt and granola isn’t actually aware of what the real world is! Have a look at supermarket shelves.. do you think they are stocked with tons of yoghurt and granola purely for dream world inhabitants?! Bizarre.

I’ve never ever bought granola.
Yoghurt is flavoured, not the plain stuff you might have with granola.
I might eat it on holiday if it’s available but I wouldn’t buy it.

There is nothing that is not simple about either yogurt or granola. To suggest that normal people in the real world dont eat it is just daft. Granola and yogurt have been a breakfast staple for a very long time. Consumption of granola is actually going up year on year and traditional cereal like cornflakes shredding etc is going down. OP offered what she eats as that is her normal. I have ever never bought normal cereal in my entire adult life. I buy, porridge oats granola and weetabix. Many of my family and peers are the same.

That I can understand but MIL was more pass ag about it and heavens to Betsy, the woman had been a Deputy Headmistress!

My grandpa was a lovely man but when my granny was alive she ruled the roost, right down to laying out his clothes for him (i.e. she decided what he was going to wear, and he meekly went along with it). After she died I think he struggled with the idea that he now had to make his own decisions. I remember going out for the day with him and when the whole family sat down in a cafe and orders for tea and coffee were being taken his response was 'I'll go with the majority'. Not much help to the waitress!

I'm not convinced it's an age thing, more a lived experience thing. My granddad, who would be about 120 now, spent a lot of time in India during WW2. He developed a real taste for hot spicy food and when an Indian restaurant opened in our town in the late 1960's, he would drag my nan there at least once a week. He would definitely have embraced other 'foreign' cuisines. My nan, wouldn't eat anything with a vaguely foreign sounding name. I remember making a french bread pizza and having to tell her it was ham cheese and tomato on toast. She loved it!
My mum, born just a few weeks before WW2 started, was not used to 'fancy' food at all. She was brought up during rationing when food tended to be plain and straightforward. Like others on here have said, she wouldn't dream of getting off fat when making a casserole or similar. Her idea of an exotic meal was to bung a pound if mince and about three chopped onions in a casserole dish with an Oxo cube and water. When it had cooked in the oven for about three hours, shed add a bit of ketchup and call it bolognese. As a child our meals were pretyset - roast on Sunday, leftovers with bubble and squeak on Monday, Tuesday would be liver, Wednesday sausages, Thursday fish fingers, Friday macaroni cheese and fish and chips on Saturday. Even up to when she died earlier this year, she was very much a creature of habit. DH and I, in our 60's and 70's, will try most things and both love an Indian or Chinese. I cannot eat Tex MEX type food as an operation several years ago means that anything with much chilli, physically hurts and there are a couple of ingredients I don't like, but other than that, we'll try pretty much anything. My adult ds's, will not only eat most things but will cook them as well.

As bad was MIL's habit when offered a drink. "What is there?", red, white, pink, g&t, sherry, etc. "well, what are you having".

I concluded after the first 15 years that it was a ploy to make someone else take responsibilty for her choices. "Well They said they were having white, so I had that, but I think I'd have preferred red". My response then became, "never mind what I'm having, you can have what you want, so what do YOU fancy?".

I remember my fil replying "oh, anything!" With a dismissive wave of the hand when I asked what he wanted to drink once. I gave him masala chai..he whispered to my husband he didn't like it