Food insecure

At times during the year, these households were uncertain of having or unable to acquire enough food to meet the needs of all their members because they had insufficient money or other resources for food. Food-insecure households include those with low food security and very low food security.

Low food security

These food-insecure households obtained enough food to avoid substantially disrupting their eating patterns or reducing food intake by using a variety of coping strategies, such as eating less varied diets, participating in Federal food assistance programs, or getting food from community food pantries.

Very low food security

In these food-insecure households, normal eating patterns of one or more household members were disrupted and food intake was reduced at times during the year because they had insufficient money or other resources for food.

I'd say Ramen only would fall under low food security, because it's a less varied diet.