Is it highly unlikely that someone would have deficiency in vitamins of any kind in today's world?

[kenny1999]

I'm living in a developed country where I have never experienced starve, I may have experienced overweight more often. I know that, I understand that for a balanced diet, one cannot live with fruit and vegetables. Here I have two major questions about this.

1. If I haven't had ANY fruit or vegetables for a few months but I still take in meats and carbohydrates, could I have deficiency in vitamins of any kind?

2. If I practice fasting and do not eat anything at all for a week, and probably drink only distilled water, could I have deficiency in vitamins or other essential materials for life?

I'm looking for medical or scientific advice rather than legend or unproved information on the web sites. Thanks.

[Peterkin]

This is a proven web site

https://www.webmd.com/food-recipes/guide/vitamins-and-minerals-good-food-sources

so is this one USDA An official website of the United States government.

3 hours ago, kenny1999 said:

If I haven't had ANY fruit or vegetables for a few months but I still take in meats and carbohydrates, could I have deficiency in vitamins of any kind?

Yes, several.

3 hours ago, kenny1999 said:

If I practice fasting and do not eat anything at all for a week, and probably drink only distilled water, could I have deficiency in vitamins or other essential materials for life?

Unlikely.

another informative site Dietary Guidelines for Americans, 2020-2025 and Online Materials

[CharonY]

4 hours ago, kenny1999 said:

2. If I practice fasting and do not eat anything at all for a week, and probably drink only distilled water, could I have deficiency in vitamins or other essential materials for life?

As an addition, unless you are still developing, nutrition is an ongoing process and issues arise because you deplete your reserves (which could happen during fasting) but deficiency (i.e. lack of something) obviously goes away once the nutrients are coming in again. I.e. anemia is not a live-long condition.

There is the that certain nutrients that are not easily absorbed (e.g. B12) can take a long time to replenish once they drop below a certain threshold. In these cases supplements and injection might be needed in addition to a balanced diet. 

Edit: I should also add that there are a range of conditions that could cause in anemia despite a balanced diet.

[TheVat]

Fasting for a week, it's not uncommon for fasters to drink lemon water with a tiny pinch of salt.  Metabolically, it doesn't have enough to activate calorie absorption (or stop ketosis), and it helps keep electrolytes up.