Yes, you always need to take insulin to cover the carbs you eat if your body does not make its own insulin. That said, taking insulin doses too close together can cause stacking. You want to be beyond the peak time of your insulin before giving another dose - - Humalog 1-2 hours, Lyumjev 15 mins-1/2 hour.
I take Humalog, and have found that if I eat lunch 2 hours after breakfast I can dose for my full lunch and will be fine. This may not be true for you though, as there are many contributing factors like insulin resistance or gastroparesis. So, talk to your doctor, NP, or diabetes educator about what you should do!