I can't really tell what you were thinking here.

Oatmeal is nutritionally identical to cereal for the obvious reason that that's what it is.

Here's the nutrition sidebar for Quaker Oats rolled oats versus Cheerios:

                   +---------+----------+
                   | Oatmeal | Cheerios |
    +--------------+---------+----------+
    | Serving size |    40g  |      39g |
    +--------------+---------+----------+
    |     Calories |    150  |      140 |
    +--------------+---------+----------+
    |          Fat |     3g  |     2.5g |
    +--------------+---------+----------+
    | Carbohydrate |    27g  |      29g |
    +--------------+---------+----------+
    |     (sugar)  |     1g  |       2g |
    +--------------+---------+----------+
    |     (fiber)  |     4g  |       4g |
    +--------------+---------+----------+
    |      Protein |     5g  |       5g |
    +--------------+---------+----------+

Here are the UK figures for Cheerios multigrain and Quakers rolled oats. Cheerios have 17x the sugar. I think they used to be worse in the past before UK sugar regulations led to lots of changes to breakfast cereals.

I use 100g because they have different servings amounts. In the UK, the serving size is just 30g not 39g.

I would note that reducing such foods to tables can miss the point. They make me feel very different to eat. One is a very moreish sugary frankenfood that makes me lose control of my appetite. I can eat it by the box. The other is something that makes me feel good but if I make too much, I'm done and can't finish it. Eating an excess is physically hard.

                   +---------+----------+
                   | Oatmeal | Cheerios |
    +--------------+---------+----------+
    | Serving size |    100g |     100g |
    +--------------+---------+----------+
    |     Calories |    374  |      378 |
    +--------------+---------+----------+
    |          Fat |     8g  |     4.8g |
    +--------------+---------+----------+
    | Carbohydrate |    60g  |    69.1g |
    +--------------+---------+----------+
    |     (sugar)  |   1.1g  |    17.7g |
    +--------------+---------+----------+
    |     (fiber)  |     9g  |     9.6g |
    +--------------+---------+----------+
    |      Protein |    11g  |     9.9g |
    +--------------+---------+----------+

Those don't look like plain Cheerios, but one of the many sweetened varieties.

I haven't seen a sugar-free variety in UK supermarkets. Standard Cheerios have always been sweet. I would call the "sweet" varieties things like Honeynut which have 22.4g of sugar per 100g.

Hmm, seems plain Cheerios are indeed not available in the UK; [1] shows only flavored versions...

[1] https://www.nestle-cereals.com/uk/brands/cheerios

The "low sugar Vanilla O's" sound ridiculous but contain comparable sugar to base Cheerios.† Presumably they have more vanilla flavoring.

† Which is to say, there's still a bit of added sugar, but not much, just like in the base Cheerios. (The rolled oats have no added sugar. The difference between "1g" of sugar in 40g of American rolled oats and "1.1g" in 100g of British rolled oats must be down to either different oats or rounding errors.)

I feel like the constant addition of relatively small amounts of sugar to random foods that aren't even supposed to be sweet might be a bigger issue than the inclusion of big heaps of sugar in foods that are supposed to be sweet. It's difficult to find beef jerky that is less than 10% sugar by weight. Rice Krispies are also 10% sugar by weight. There's no good reason for this.

In the US, our "regular" Cheerios aren't the Multigrain kind. They're minimally sweetened, and mostly made of oat flour. See them here: https://www.cheerios.com/products/original-cheerios

Cheerios multigrain are a sweetened version

If you ask for Cheerios in the UK, this is what you get. If you get an own-brand Cheerio knock off called "Hello Loops" or something, they will have also the same level of sugar.

Might explain some of the confusion in this thread.

Here in DK we also have the usual American brands which are all full of sugar. I haven't seen anything sugar free.

The more healthy products are marked with a green mark. None of the usual brand has it because of high sugar (or sugar like) substances contained.

https://www.sundhedsplejersken.nu/familien/kostanbefalinger/... .. in Danish so you might want to Google translate.

Cereals are typically more processed than oatmeal (especially when we talk about uncut oat meal). If we talk about instant oatmeal vs cereal, then I don't know it matters a lot, sure.

I've got some home brand "100% wholegrain" oats here that say they contain 1g Sugars per 100g, less than half 1g per 40g shown in your table.

And even 1g per 40g is double 2g per 40g, not 'nutritionally identical'.

Do you have a point?

Here's Shredded Wheat: https://www.postshreddedwheat.com/products/the-original/

0g sugar per 60g serving size. Do I now conclude that you were trying to fool me into thinking oatmeal contains less sugar than cereal when in fact it contains much more?

No, that's nonsense, oatmeal is a kind of cereal. The amount of sugar in it isn't even related to whether it's oatmeal.

Oats are low GI and breakfast cereals are high GI

Oatmeal (if unsweetened/unflavored) has about the same GI as orange juice or cake made from some Betty Crocker boxed cake mixes and is just slightly lower-GI than the American formulation of Coca-Cola (see #333 Oatmeal (Canada), GI value of 54 ± 4 in the table at https://www.sciencedirect.com/science/article/pii/S000291652...).

I think oatmeal and other high-GI foods are promoted as low-GI in hopes of helping wean diabetics and pre-diabetics off of even worse foods (e.g. something really bad like powdered donuts), akin to how methadone is used to try to help heroin addicts. But genuine low-GI foods would be things like eggs, cheese, or chicken breast (all with nearly 0 GI) or some raw veggies like raw broccoli or the greens in a leafy salad (in the neighborhood, roughly, of 10-20 GI). Cooking low-GI vegetables like broccoli defeats the purpose and raises its GI to around the same value as oatmeal.

I wrote oats, not oatmeal (I don't think we really use that term in the UK). AIUI "Oatmeal" can refer to various things, including high GI porridge.

I only buy steel-cut oats, which various sources on google say are around 42 GI [0][1]. I do concede that any form of oats are on the upper-end of low and/or medium, and aren't some magic super food and one should not focus just on GI.

Steel cut oats are definitely better than most breakfast cereals however.

Joel Fuhrman in his book on reversing diabates also recommends small portions of oats (but mostly says to eat veggies).

[0] https://www.canr.msu.edu/news/steel_cut_oats_are_a_nutrient_...

[1] https://www.nutritionletter.tufts.edu/ask-experts/q-before-c...

Oatmeal is cereal; and it comes in a range of sugariness, as does the kind of cereal intended to be eaten cold.

I think the point was that oatmeal IS a cereal

Oats are a cereal grain.