To address your comment on research in nutrition/ dietetics … depends on the population group, overall diet and fatty acid balance. The Clever Guts Diet has little in common with the standard western diet. It is not specifically targeted to those who need to lose weight, have hypercholesterolaemia or other risk factors for cardiovascular problems.
Over the long term we are encouraged to eat a modified version of the Mediterranean diet. A really wide variety of plants, olive oil, oily fish and other seafood, grass fed dairy if not identified as problematic, and so on.
if anyone has a medical condition that is affected by diet and lifestyle, they absolutely need to run a major change of diet past their medical team, and modify as necessary.
When still practising I would have been delighted if any of my (lifestyle healthcare) clients had brought this diet book to me. I constantly banged on about balance and variety!