Could you live off dietary “supplements” alone? Assume you have access to unlimited water. Protein shakes (proteins and carbs), multivitamins, fiber supplements - it doesn’t seem as if anything is missing.
I think you still need at least some ‘bulk’ for a healthy digestive track…
“As well as the pictures of the foods shown above, there are other important foods that we need to include into our diets; these being those high and rich in fibre as they don’t completely break down during the metabolic process and provide bulk in the large intestine to keep it healthy and to assist in evacuation of faeces. Whole grains are especially important to eat on a regular basis for good colon health.”
bolding mine
There are plenty of fiber dietary supplements.
Carbs don’t tend to occur much in supplements. But several of the fruit or veggie in a pill or powder do contain some. You’d have to get most of your calories from protein.
Your body can’t process enough protein though to get most of your calories from it. True, it is a myth that you can only digest so much protein per meal, but your body can only absorb so much protein in a given time; even whey protein is limited to about 10 grams per hour (if you eat 100 grams of whey protein at once, you will take 10 hours to absorb it all), or about 240 grams per day; this is only 960 calories, so even a completely sedentary person will need to get about 500 calories from other sources. Some of the protein supplements (not plain protein powder) can have a lot of carbs though and they even sell carb supplements (the idea being that you want carbs that are absorbed as fast as possible and with the highest glycemic index; ordinary table sugar is actually less effective than foods like bread).
Here’s a somewhat related question: Can a person live off of Milk, V8 Juice and multivitamins? I’m guessing the total lack of solid food would totally mess up digestion in some horrible way.
If you’re accustomed to solid food, it can be physically quite difficult to ingest a full balanced diet in liquid form - thick protein shakes and soups tend to make you feel full up before you’ve swallowed enough to keep you alive - and they keep you feeling full for longer.
(I speak from recent/ongoing experience of an imposed liquid diet, and despite drinking as much as I could of rich, barely-liquid shakes made from peanut butter, milk powder, etc, I rapidly lost quite a lot of weight)
The short version is that there are products specifically designed to provide long term liquid nutrition, usually given by NG to those who are unable to eat. Given that people can be maintained in a comatose state on such “supplements” for decades it is clear that living off of supplements is indeed possible. Ideal for health? No, of course not, but that was not the question.
Protein shakes have almost no fat (although the weight gainer formulas have protein and carbs in them, so that is 2 macronutrients).
I don’t know what health risks, if any, will come from a long term diet where fat content is 5% or less. If anything it may be healthier.
Actually, if you tried eating a fat-free diet, you’d end up getting very sick because you wouldn’t be getting any of the essential fatty acids. As for health, indigenous groups have subsisted fine on diets with fat making up a majority of calories (note however that they didn’t eat processed foods, including processed meat and grains and vegetables with extreme amounts of omega-6s, “prothrombotic, proinflammatory and proconstrictive”; even saturated fats have health benefits).
You can easily get all the fat you need from supplements, what with EFA and Fish oil.