My prior probability that any diet consisting solely of rice, water and any one X is a bad idea is very high. I'd want to see very strong evidence that scallops really do contain everything a human needs to remain healthy.
Many of the other extreme elimination diets I tried showed obvious signs of micronutrient deficiency. For example, I tried bread and water, lean meat and water, etc. It's easy to recognize signs of deficiency - fatigue, cravings, etc.
But I wouldn't say scallops have everything. I did lose weight. I think you'd have to add in some fish to get a complete diet. Not so much for vitamins or minerals, but for something related to satiety and macronutrient composition. It could be insufficient fats/oils, or maybe you can't get enough protein because it triggers s...