I will be making cakes for a baby boy (turning 1) who will have his 'smash' cake separate from guests cake. He suffers from serious acid reflux.  (So serious they used scope to make sure there were no serious causes. Turns out it is something he will have to outgrow as no known causes were found in that procedure.) My first thought was to look for icing w/as little fat content as possible. Guests cake will be iced in regular buttercream icing.  His cake will be white cake. (minimal fat)

Here are the 3 icing possibilities: (1)

Here are facts re: bettercreme:   ~~ Nutrition Facts serving size: 2 TBSP (35 G) AS LIQUID Amount Per Serving Calories: 130 Calories from Fat: 80 Per Serving % Daily Value * total fat 8g 5% saturated fat 8g 14% trans fat 0g cholesterol 0mg 0% sodium 25mg 14% carbohydrates 13g 2% dietary fiber 0g 0% sugars 13g protein 0g. 

(2) Buttercream (made w/cake & icing shortening, not butter) * no idea on facts re: fat content

and  (3) Cream Cheese Buttercream (made w/cream cheese & cake & icing shortening) * again no idea on facts re: fat content

Any idea which would be best for this little guy?  I'm thinking the bettercream (whipped type icing) would have the least fat.  Any input at all?  I am sure he will not be getting to eat much of it, mainly a photo op, but want to offer best possible choice. Thanks!   

why not just glaze the cake with a powdered sugar and water glaze? i have a nordic pan that's a train set--it's adorable just glazed you can add detail with markers or paint but he's one year old--he doesn't care about his cake beyond what's age appropriate--just glaze his cake if fat is too hard for the little guy--i make pound cake in it--not that you have the pan but i mean just a glaze is an idea--keep it simple and safe is my idea for you

AI have gerd, oh the joys, I find sugar is way worse than fats for me. I would suggest using a site like myfitnesdpal to input your recipes and get the nutritional amounts from there. Then maybe show his mom and ask her? She will probably have a better idea of his tolerances than anyone here. personally, I can eat imbc made with xylitol til it comes out my ears with no reflux, but a few bites with regular sugar, and I'm on fire.

make 7 minute icing or boiled icing.  There is no fat and it is great for kids.

^ Here's the topper.

K8memphis, his theme is a cowboy type theme & his smash cake will be iced white w/a topper added. (Small cowboy holding a 'toy' pony w/his name spelled out on blocks.)  So there will be no other decoration needed really other than the topper she had made for his cake.)  I love the idea of the IMBC, and thank you for your personal, first hand knowledge/experience scrumdiddlycakes.  Also loving the idea of the 7 min icing matthewkyrankelly.  Many thanks!  Have until Wednesday to decide!   

LOVING your recommended site scrumdiddly!  Thank you!

Icing with as little fat as possible........7 minute icing is only egg whites and granulated sugar. no fat at all.  Like Matt said. You just have to keep it in the fridge. 

I have looked up nutrition facts on (1) Buttercream (2) Bettercreme & (3) Seven Minute Frosting.

Gave these facts to them & will use which ever the babies mom & grandma decide on. 

Thank yall for the GREAT suggestions!!!