Upset tummy being caused by my Mothers need to constantly eat though she'll only eat sweets, chocolate or biscuits. How do I stop her?

I think that you need to discard the idea that mom's eating "rubbish" is what is causing her loose bowels and investgate the real cause.

There are many healthier options you can purchase or prepare that when put into a nice jar or tin can easily be switched for less healthier junk food choices. In general eating junk foods tends to cause constipation and not diarrhea.

"No added sugar" varieties means they have sugar substitutes. They can cause problems. Buy healthier versions with natural sugars like honey or stevia, or regualar sugar which is better. My mom has same problem. Always has to be eating somthing sweet. But found the sugar free varieties which we thought would help her not gain weight were actually giving her stomach issues and headaches.

I would get a gummy vitamin and a good probiotic with prebiotics and give her those daily, then let her eat what she wants.

You can make fruit bars, strawberry shortcake, homemade jam with honey instead of sugar. Do smoothies that have veggies and protein with a sweet base so she thinks she is getting junk and really getting some nutrition. I freeze my fruit so it is very much like a milkshake, add almond milk, carob powder for chocolate taste, apple for fiber and banana for potassium, blueberries for antioxidants and pecans, walnuts, almonds for protein. Dates, raisins and figs are great for added sweetness. You can make a large batch and freeze or refrigerate for up to 5 days. Partially frozen can be served as icecream, leave out almond milk and it's like a sorbet.

Have to be creative with sugar seekers.

Honey is also a really great substitute for sweet, find a local source for raw honey and that is another great source for nutrition.

I think you should avoid fiberous fruit & veggie smoothies until you figure out what is really causing her bowel issues.

Is your mother diabetic?

If shes not, then why are you concerned that she likes to nibble on cookies? Let her eat cookies!!

Sugar Free Sweets with Sucralose or Splenda will cause diarrhea if eaten in any quantity.

Try to find sweets that use different sweeteners. Some like Xylitol or Stevia. Be aware that Xylitol is deadly for pets.

Will Mum eat dairy? Puddings etc? I know you likely do not have much time for cooking from scratch, but what about homemade pudding with sliced banana?

Homemade Oatmeal cookies, perhaps with added grated carrot?

Gob Stoppers probably do not come in sugar free versions, but they would give her something to suck on for a very long time.

Will she eat cottage cheese fruit salads?
I make one for my aunt which is a small box of dry orange jello mixed with 8 Oz cottage cheese, drain a small can of pineapple tidbits and a small can of mandarin oranges, stir into cottage cheese mixture then add a small container of cool whip. You can mix this up in 5 min.
Its semi healthy as it has some protein with the cottage cheese if she eats dairy. It’s pretty and looks like a dessert which it does have plenty of sugar.
About artificial sweeteners. You need to experiment with the sweeteners. Some of them will raise her blood sugar as much as real sugar. A slice of bread is sugar to the body. If you can get protein in with the carb it will slow down the sugar. Plus a heavy carb diet will make her crave more carbs.
Do try the prebiotucs and probiotics. Also try to add fiber in something. You can get PBX fiber in a capsule or stir into a liquid. The fiber will help satiate her as well as fats. Avocado. Olive oil. Coconut oil, grass fed butter added to anything you can get her to eat will make her feel more satisfied.
just curious, what does her blood sugar run? Do you check it or is this only from her dr visit blood work?

Thanks everyone. Her upset tummy is caused by 'no added sugar' sweets that she eats constantly which is why I'm looking for an alternative. If she doesn't have one of those in her mouth then she's looking for biscuits & chocolate.
She won't have a smoothy as it's not solid (not food to her) & she can't have gummy sweets or any nuts due to loose fitting dentures. She's not allowed any fruits like strawberries with seeds in due to a different bowel issue. Refuses anything cold like ice cream temperature.
Mum does eat grapes & blueberries with her lunch but if I give them with a cup of tea she complains, refuses & looks for biscuits.
She's a tricky one to feed........

It could be nausea..I am not really sure. You may want to get her checked out at the doctor. If it is, then they will prescribe a medication for that. You may want to try stuff like potato pancakes, pudding, Toast, etc. It helped my great aunt when she was unable to eat anything. You may want to try a nutritious drink like balance or fruit smoothies. Yogurt is also sweet but a good probiotic, it can really help with the liquid runs (sorry to be gross, but I can't spell the d word), plus it has protein in it (Look for the ones that have protein in it). Ask the doctor if she can be on vitamins or supplements.