Eat the plants, they are good for you and good to eat. I do not think that modern diseases of civilisation are caused by people eating vegetables and fruit. Even the Innuit ate foods like seaweed and berries when they could.

This is no reason not to also eat organ meats which are some of the most nutritious parts of the animal. Depending on where you live liver is usually available, is easy to cook and packed with protein, vitamins and minerals. Heart and kidneys are also good. Organ meats also have the benefit of being inexpensive to buy.

I have benefited greatly from eating organ meat, most importantly beef liver. I have had issues with adrenal fatigue, am recovering from chronic illness and found that vitamin/mineral supplements were never enough to keep my nutrient levels up and give me energy. Since eating liver, kidney, heart, bone marrow and oysters, I have noticed a huge increase in energy. I guess most normal people might not notice these effects but if you're sick and fatigued you probably would. I highly recommend it.

I can't say much about getting nutrients from plants as I never could eat enough to make any difference in my health or energy.

As for numbers, my B12, folate and iron have been on and off low for years. I took supplements which brought my levels to low-normal in each range. Now without supplements and eating organ meats, I'm sitting in the high-normal range.