Active 5 yo, slow weight gain

[Superscientist]

I'm after tips to help with a very active 5 almost 6 yo with slow weight gain. Since turning 4 her weight gain has slowed significantly.

She was a good weight but very short as a toddler, around 1st percentile for height and between the 25th and 50th for weight. This put her on the 91st percentile for BMI, her paediatrician and dietician were happy as although she was a top of a healthy weight she looked "normal" and fitted in clothes based on her height rather than weight. At 3 she was still in 12-18 month clothes. She also already had a very limited diet as at the time so they didn't want to change her diet much more and she was a poor eater. She had a lot of food allergies, severe silent reflux, damage to her teeth from the reflux and toddler diarrhoea too.

Her reflux, teeth and toddler diarrhoea have improved but since turning 4 her weight gain as slowed a lot. Since September 2024 she has only gained 1.4kg and between July 2025 and Jan 2026 she only put on 200g. She has gone from just under the 50th percentile to the 9th percentile for weight but as her height has gone from the 1st to 2nd-9th percentile her BMI has gone from the 91st to 35th percentile and is still actively dropping.

She has a low appetite and is generally uninterest in food. She can't have dairy, soya, eggs, coconut plus other things. She doesn't like nuts and milkshakes so can't sneak extra calories in that way. The dietician has said we need to try to get an extra 500kcal in her a day and is going to send us a trial pack of fortified drinks to try but I'm apprehensive about her not liking them, we only have one option too because of her combination of food allergies. She will only drink oatly barista oat milk and refuses any other oat milks, even when she hasn't seen the carton so doesn't know it's not her usual one so her tastes can be quite specific

She walks to and from school every day which is 15-20 minutes, runs around lots at break times - the head teacher has said she is a child that really throws herself in to things fully. She has swimming, football and squirrels (scouts) each week. The paediatrician and dietician are happy that she's is still clearly eating enough to be active as well as gaining on height but concerned about the impact her fairly static weight might have longer term. She was tested for coeliacs as a toddler and had stools samples tested when she was 3 to look for malabsorption and inflammatory markers both came back normal

Honestly I would ask for another coeliacs test just to be certain. Does she get mouth ulcers, complain of aches/pains, has she ever had her iron checked?

My DD was slow to gain weight from the outset. She also had allergies to dairy and eggs when she was younger and never liked eating much meat so getting fat into her was a bit tricky. Like your DD she is nevertheless very energetic and engaged with everything which was reassuring.

Our dietician told me to add a good pudding every day so I made things like rice puddings, crumbles and custard (all made with dairy free alternatives). Also plenty of snacks but I always go for proper food rather than processed stuff as our bodies can't digest things like anything called 'gum' which can lead to gut issues as well.

I did painstakingly slow milk and egg ladders with DD. She completed the milk ladder at age 7 and can now eat dairy. We're still working on the egg ladder and she's 9. Has your DD been able to try the ladders? Even if you only get to the 'well baked with starch' rung with milk and egg it gives so many more pudding options to eat. Also many people with a dairy allergy can tolerate butter anyway which is a much better option than margarine. Have you been able to explore whether your DD can eat butter? Obviously if it's an anaphylactic type of reaction then you can't mess about trying things.

Regarding your DD's soya allergy, I myself have a soya allergy and the stuff gets absolutely everywhere especially if eating out. Soya oil is widely used and although the official line is that the soya protein levels are low enough in the oil that they aren't a problem, my stomach says different. If I eat something cooked in soya oil it gives me an upset stomach and the skin inside my mouth gets sore. As your DD gets older it will be easier to make connections between what she eats and milder symptoms like sore mouth which might suggest a food is worth avoiding.

Sorry all that is rather a ramble. I'll wrap up by saying that my DD eats plenty now (she is 9) yet is still on the skinny side. I think it's just the way she is built. Height wise she seems to have caught up. I worried quite a bit about her weight until fairly recently so I understand where you're coming from.

Very rarely has mouth ulcers, may be once a year, often complains of aches and pains but also takes quite a few tumbles and seems to bruise easily

Her iron levels haven't been checked since she was about 2. It might ask for them to be checked again at her next paeds appointment and another coeliac test too thanks @Realisation14

Her allergies aren't severe as in they are mostly gut symptoms rather than anaphylaxis but she's very sensitive. We haven't been able to progress passed crumbs on the milk and egg ladders. We have recently tried to introduce coconut in the form of , I vegan cream cheese and we managed half a teaspoon once a week and went we went to several times a week she reacted and now can't tolerate once a week either

We don't allow anything cooked on soya bean oil as until recently she reacted to soya fed poultry and could only eat corn fed chicken and no turkey.

We struggle with desserts, she doesn't like custard or rice pudding. We try most nights to give her fruit and yoghurt with nuts or granola on top. We have to bribe her to eat the yogurt with the promise of fruit afterwards. Some evenings we run out of time for pudding as she can sit Infront of her dinner for half an hour before starting to eat it. She can only have the oatly greek yoghurt and no commercial ice cream which is a pain!

We have had a weekend where most of her meals have been out and it's really highlighted how rigid she can be. She was given a ham sandwich, with plain crisps and orange for lunch on Saturday and chicken nuggets and chips at a party on Sunday but refused to eat them as it was different ham, bread, crisps, oranges and chips to the ones we buy. It could well be the level of processing that is the problem. We buy whole foods as much as possible as we find it the easiest way to avoid her allergens. When we buy chips it's the chips that only have potatoes and oil in the ingredients, we make our own bread and just generally stick to foods that have the fewest ingredients in. She can't have tapioca, pea protein and carob which are mostly found in ultra processed foods. We have issues with colours and flavouring too as she can't have tomatoes or paprika

I feel like we need more input but not sure from where. I wonder how much is physical and whether some psychological input would also help

Hi @Superscientist ! That's really tricky with all her intolerances, plus of course the poor wee thing has reason to be cautious of unfamiliar food – food has caused her so much pain.

Would she be okay with things like you adding olive oil to her vegetables, more spread on her sandwiches, a spoonful of peanut butter in her porridge, those sorts of changes?

If she likes fruit, does she like dried fruit? You can get quite a wide range now, and if she likes something, online wholesalers have bigger bags much cheaper per 100g than the supermarkets. A mix of dried fruit, nuts, and maybe a few plain chocolate drops could make a high calorie snack or pudding. Or would she eat any of the 'energy ball' type recipes? You could dip them in hundreds and thousands if that would encourage her. Not a hugely healthy option, but something like flapjack for pudding? You can get some nuts or seeds or nut/seed butters in there to improve the nutrition a bit.

I realise it's not ideal for teeth, but are there times in the day when you can squeeze in a quick extra few bites? Walking somewhere, waiting for something, etc.?