Do we need to take vitamins and supplements?

I did not think this was such a hot-topic of debate, but since dipping my toe in to this world I realize there are a lot of opposing opinions here. It seems that the vitamin industry is huge, and I saw a statistic that in 2016 the supplement industry in just the USA was worth $122 Billion dollars per year. So, intuitively I know that there are going to be some bad actors in that market, people taking advantage of the sick or those worried about getting sick. Now, when I see advertisements saying that I need to take more of some vitamin or new supplement in order to be healthy, I am always a bit skeptical. Then, I read about how much of the medicines and vitamins we take are not even absorbed, we just end up excreting them from our bodies and this is messing with aquatic ecosystems.
So, for a normal person with no health problems, that eats a good diet, are all these extra vitamins necessary or am I just paying a lot of money to make expensive urine?

Do you believe in Alkalizing diets?

I have been hearing about alkalizing diets, they are supposed to reduce inflammation and prevent many diseases including cancers. But, I have also seen a lot of info that says there is no way to alter your blood pH through your diet. With these conflicting points of view, I can only assume that all the science is not there yet either way. So, what do you think?

Cut back on coffee?

I'm a pretty big coffee drinker- I just love the stuff! I only have 1 or 2 cups a day (sometimes 3), but some people would still say that's a lot. I feel great when I drink coffee, but I do feel it when I don't drink any. Would you say that I should cut back on it to the occasional cup, or keep on drinkin'?

Raw Cookie Dough

Is it ok to eat raw cookie dough? I am debating letting my children eat frozen raw cookie dough. I know that eating raw eggs isn't supposed to be healthy for you but if they are pasturized and it is frozen, I think it should be fine. What do you think?

To fast or not to fast?

I've read many things about the benefits of doing intermittent 3-7 days fasting, usually once or twice a year.

I've also done a 3 day fast once, before I went on a restrictive diet (for medical reasons). At that time, I saw the benefits of less sugar cravings and being more able to control what I eat.

I'm about to go on a Slow Carb Diet, which essentially restricts the amount of sugar and specific carbohydrates you eat. Will it be beneficial for me to do a 3-day fast before I start?

Bonus: If you've done a fast before, how did you go about it? How did you feel from it?

Carbs at Night?

I heard that it is unhealthy to eat any carbs anytime less than 5 hours close to bed. I've also heard it's healthy to eat complex carbs right before bed. What is your opinion?

Good Carbohydrates

I heard that the only carbs healthy for you are brown rice and sweet potatoes. I like to eat whole grain pasta and bread too so I would like some input on what you guys think. Feel free to leave opinions in the comment section.

Dieting or Exercise?

I am trying to lose weight and have been eating healthy and working out consistently with a variety of workout types for around 6 months now, but haven't seen any changes. What am I doing wrong? Should I continue doing the same thing or should I try changing my diet and/or my workout routine again?