Oatmeal isn't exactly an alternative to cereal.
There's instant oatmeal. The kind that comes in packets and you just add water. Often has sugar added, often slathered with sugar. Possibly worse than a bowl of corn flakes. Highly processes with most of the starches and cellulose (fibre) reduced to simpler forms and readily and rapidly converted to glucose in the gut. High GI. Almost like candy.
There's quick-cooking AKA minute oatmeal. Gelatinizes in 3 minutes on the stove or the microwave. Still processed so the starches are easily digestible (that was the point when it was invented). Slightly better than instant oatmeal and corn flakes but still mid-level GI and GL.
Finally, there's oat meal. Steel-cut oats are just the seeds of the oat plant lightly crushed into large pieces. Not pre-cooked. Most palatable when cooked overnight. Very high in non-digestible fibre, mostly still complex starches that take considerable time to convert into glucose in your digestive system. Low GI.
It's oat meal that is most associated with glucose and blood pressure control, not so much oatmeal. Rule of thumb: the longer it takes to prepare, the more it takes to digest and the better it is for you if you're concerned about a healthy diet.
But the point is that oatmeal is not oatmeal, and discussing it as if it is is always going to be misleading.
That's still "oatmeal". "Oat meal" would be a slightly odder way to say oat flour.
Of course you can "speed up" the process by blending them into a smoothie.
If you toast the oats first to make them crunchy, it's no longer the dish called "oatmeal" (which is a porridge) but now it's a kind of granola, which can be used as a breakfast cereal.
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 |
+--------------+---------+----------+And even 1g per 40g is double 2g per 40g, not 'nutritionally identical'.
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.
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 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...
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 |
+--------------+---------+----------+† 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.
Might explain some of the confusion in this thread.
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.
Right, its within the space of breakfast cereal, not an alternative to it.