Human science knows that the body requires some specific nutritional items on a daily basis. Interestingly enough, without them there is a dysfunction, long term or short term.
Human physiology requires 12 essential vitamins, 17 essential minerals, 9 essential amino acids and daily essential fatty acids. If these components are not in your diet, you need to supplement.
A good multi-vitamin/mineral can pick-up where your foods may be deficient in these two areas. Meat of any kind at least once a day is a complete protein with all nine essential aminos. If we ate fish often enough to achieve EFA needs, we would not need to take fish oil supplements.
I addressed these needs years ago by formulating a food grade natural vitamin and mineral capsule called "VitaPerfect". Not expensive and easy to take. My fish oil capsule "OmegaPerfect " is high in EPA/DHA by taking one or two a day. No burp with this one.
So if you eat at least one helping daily of some kind of meat including fish, or chicken, or turkey, or red meat, you are getting your 9 essential aminos. Taking protein powder is for those that are exercising vigorously and can't eat enough meat to satisfy the essential amino acids or muscle hypertrophy needs.
So many of our foods today are depleted of the nutrients they once had years ago. You simply don't know what you are getting. You can guarantee you are receiving these essential items by supplementing appropriately. When I am consulting people about health issues, I first want them to guarantee me they are creating a fundamental base-line of health by including these necessary elements either in their foods or in supplements. Often health issues improve simply by focusing on the items mentioned.