My DD is overweight and I have a history of eating disorders

Firstly try not to worry. Secondly I would look at what your other children are eating because lots of sports doesn't mean lots of snacks, they need appropriate nutrition for their calories expended but that's in the form of meals not snacks daily (apart from a piece of fruit or vegetables) - I have a daughter who played a lot of sports, still does as an adult and she never had regular snacks.

Portion sized are to some extent proportional to body size. Your 3 yr old knows they are much littler than your older girls.
Try to avoid giving snacks in big individually wrapped portions - eg. A full sized magnum type ice cream. Either buy snack things in ok portions for a 3 yr old (eg, get mini magnums) or buy things in family sized containers and learn to portion them out appropriately - maybe a smaller bowl + spoon for your preschooler when doling out ice cream as a dessert for example. Or identical bowls and spoons but she gets a smaller scoop because she’s smaller.

You sound like a very caring and kind parent. I think it would be about the whole family getting more healthy at a guess - so there’s no change for her that isn’t a change for everyone. No expert here!

You are smaller so you need less

Which is something a lot of adults need to learn

It's okay to say no sometimes. You could also get her a little snack box or bowl and fill it with a proportionate amount of food, ie the older ones have a bag of crisps, she has a few in the bowl/box. It is hard but it's also important for her health to keep it under control, appreciate its a balancing act though not making food a 'thing'. Also remember snacks even like fruit can cause harm to their teeth- best eaten with meals- cucumber, carrot sticks etc much better.

What snacks are they having? Do they have decent sized meals?

I’ve managed this op and I have a solution for you. It’s (drumroll) Not Particularly Nice Food.

I’m talking pork chops, new potatoes and broccoli. Fish, baked potato and sweetcorn. The kind of stuff your gran made, essentially. Crucially, you’re not denying anything* but you are providing food they will only eat if they are actually hungry

Snacks go on a timer - 11am and 3pm and that’s that. Except apples, which they can have whenever.

• Except squash. Just water to drink.

How old are the other two?

I'd start decanting everything. Get those boxes that go inside each other and she can have the smaller one.

Maybe think about the times of your meals so that nobody needs a snack after sport. If they do an activity on a Tuesday, have a meal that's quick to make or already made so it can be served as soon as you get back. Then you can say 'we aren't having a snack after netball because dinner is in twenty minutes'.

Cross posted with you there about the ages.

Boxes like these. You can get them in all sorts of places, supermarkets etc. these were the first on google.

https://www.johnlewis.com/done-by-deer-lalee-snack-box-pack-of-3-sand-green/p6221597?sppc=2dx927000709854430244mixedfashionnBAU&tmad=c&tmcampid=2&gclid=Cj0KCQjwmtGjBhDhARIsAEqfDEfVEb8JyfVMXMpTR4DHehtvu34Omvq56U9X1tYUfxJGkkSUn-10xI4aArf3EALw_wcB&gclsrc=aw.ds

I’d cut out ham as a snack for a start. It’s not healthy. Consider swapping the crisps for popcorn- plain, not sweet or buttered.

As someone whose teen daughter is currently in the grips of an ED (and was also a 'pudding' as a toddler) you are right to be cautious about this.

The calorific requirements of a growing teen can far outweigh that of a younger child so I wouldn't be discouraging your 11YO in any way - and also be conscious anything you say to your young D maybe also be picked up by the older.

You're probably aware there is a genetic proponent to ED so right to be cautious about all of them.

My advice which may be contrary to others is to try not to worry too much, take on board some of the advice on putting things into a bowl for her but I'd really try not to do anything too overt so your older DDs don't notice. If she's still a toddler her growth will be going in fits and spurts and you may find she grows out of it anyway.

I'd much rather have a slightly chubby DD and encourage an active life with no hang ups than what my DD is currently going through. As you're well aware it's hell and with hindsight we didn't help with some of the comments we made around 'healthy' food etc

Your 11 year old is old enough to understand that she needs to have some of her snacks out of sight of her sister. 'She is smaller than you so needs less food but because she wants to be like you we have to help her not always eat the same food as you'.

They shouldn’t be snacking on chocolate. Not good for their teeth. Can you remove these from a snack drawer or cupboard. Perhaps limit crisps to once a day? Offer healthier snacks like a banana or rice cakes if they are hungry.

DD3 needs much smaller portions . I would give her a smaller plate and cutlery at mealtimes.

how do I broach the subject with them. I thought of saying coz of the cost of the food shops I’m having to make some changes? Or am I over thinking this

I wouldn’t lie unless this is genuinely part of your reasoning. I think it’s okay to introduce the importance of eating a balanced diet to your older ones for health. That’s not going to give them a complex and it’s not labelling good as ‘good’ or ‘bad’. Get them on board with the multitude of resources there are available now. Just phase out the high calorie, high sugar, highly processed snacks to very occasional treats if you’ve identified these foods as the main issue why your DD is overweight. Does she have the opportunity to run around a lot as well? My 3 year old loves food and we need to exercise him like a dog daily, couple of hour’s minimum.

Honestly, when my dc were those ages and said they were hungry I'd say

'good because it's dinner time in an hour' or whenever it was. Or sometimes

'what! I haven't even thought about dinner! What shall we have? You go and get the pasta out and I'll fill the pan up'.

Mine always knew that it's ok and normal to be hungry and that the solution to being hungry is having a meal. Not deliberately, that's just what happened.

Just thinking about the portion sizes, would a bit of fun around the Goldilocks story help your little one? Big bowl for Daddy Bear, he's the biggest, Baby Bear is the smallest he has the smallest bowl, chair, bed etc, the sizes are built into the story!

I’m not sure id let an 11 yo, even a sensible one, have free rein on their snacking…but if you do she either needs to eat away from 3 yo or you need to start saying no, over and over. I wouldn’t let a 6 yo regularly decide what they were snacking on, especially one who is fussy with meals. I’d be lumping the 6 year old with the 3 year old under the umbrella of ‘food is still primarily a parent decision’.

What about getting a special crockery set with her favourites character on it? So she gets the Barbie (or whatever) plate, which is obviously smaller than a standard dinner plate because it’s for toddlers. That way her serving is different but in a good way. And portion control when you cook to ensure there’s only enough for everyone to have their serving, but make sure that there’s loads of veg. So still hungry, sure have more carrots.