Why do diets such as these rely on liquid nutrition, and not have much in the way of solid food? What advantage does that provide? I would think it better to have solids, not only for increased satiety, but more so for the metabolic cost of digestion, thus provided a slightly larger energy expenditure.
it may just be in my head, but I noticed that I seemed to lose weight faster when I included solid foods. I am currently cutting using protein shakes as my primary food source, but I include a few eggs and an avocado everyday. It would be interesting to see if there is any scientific data on cost of digestion and increased thermogenesis as a result.
Its for the ease of it both in daily life and just ease of not having or getting to decide what to eat. you already no. you cant sway or cheat you just stick to the simple effective SHORT and EXTREME plan.
Solid food is better in terms of nutrition, more filling and it burns calories digesting. However, it's also much more time consuming and harder to measure accurately. Liquid foods are easy to prepare and easily measurable. V-diet is a very extreme diet, but one of the things it relies on is that it's very simple.
You don't think about food, how to break it down, how to prepare it, etc... you don't get the opportunity to eat that extra portion and you can't measure it wrong. You drink your shake, the end.