Cheerios are made from oatmeal so yes, they are very high in carbs. They aren't a terrible carbohydrate source. Oatmeal would be better as it's unprocessed but cheerios are a much better option then pancakes or other kids cereals that are full in sugar. Just make sure to get the regular cheerios and not the honey nut cheerios which are full of sugar.
Here is the nutrition facts for 100g of cheerios. The nutrition facts aren't terrible. It has a decent amount of fibre and it's pretty low in sugar.
[TABLE="class: cms_table__yX, width: 2"]
[TR]
[TD="class: cms_table__rhe cms_table_kno-fb-ctx"]Amount Per 100 grams[/TD]
[/TR]
[TR="class: cms_table_kno-fb-ctx cms_table_kno-nf-cq"]
[TD]Calories371[/TD]
[/TR]
[/TABLE]
[TABLE="class: cms_table__yX, width: 2"]
[TR="class: cms_table__fDd"]
[TD="class: cms_table__VLb, colspan: 2, align: right"]% Daily Value*[/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip"]Total Fat 7 g[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"]10%[/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip cms_table__hDd"]Saturated fat 1.4 g[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"]7%[/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip cms_table__hDd"]Polyunsaturated fat 2.4 g[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"][/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip cms_table__hDd"]Monounsaturated fat 2.4 g[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"][/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip cms_table__hDd"]Trans fat 0 g[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"][/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip"]Cholesterol 0 mg[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"]0%[/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip"]Sodium 576 mg[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"]24%[/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip"]Potassium 641 mg[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"]18%[/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip"]Total Carbohydrate73 g[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"]24%[/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip cms_table__hDd"]Dietary fiber 9 g[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"]36%[/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip cms_table__hDd"]Sugar 4.4 g[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"][/TD]
[/TR]
[TR="class: cms_table_kno-nf-nr"]
[TD="class: cms_table_ellip"]Protein 12 g[/TD]
[TD="class: cms_table_ellip cms_table__Igc, align: right"]24%[/TD]
[/TR]
[/TABLE]
If you want something low carb to eat for breakfast, stick with vegetables, eggs, and lean meat. You could make a big omelette with some lean ground turkey and vegetables in it.