We are not statistics.

 Diets: how scientists discovered that one size doesn’t fit all

Scientists and doctors have always known this. Their error has been to never sufficiently emphasize that. The consequence being the general public is left with the impression that the dietary advice they receive is based on science when it is based on statistics. That has been big lie of so much dietary advice and I am surprised they have persisted with it for so long. Even for participants in a study the results of that study may not be applicable to them. We have to treat ourselves as individuals and unfortunately that requires considerable work to determine what works best for our bodies. 

The best advice I ever received from a doctor is "listen to your body". I did, and it told me that no matter how hard I try will always carry some extra weight and the pay off is that I can quickly pile on muscle. 

It's obvious that we don't share a common physiology. Some people can eat high caloric foods and then there are people like me who can spend one day of indulgence and see the weight scale spike. I can also spend one week going to the gym and see the gains whereas I have known other people train for weeks with what I would consider pitiful gains. 

For any given food, some people’s glucose levels would spike dramatically, while others hardly seemed to react at all. This couldn’t be explained away as a random fluctuation because the same person responded similarly each time they ate that particular food. For one middle-aged woman, for example, her blood glucose level spiked every time she ate tomatoes. Another person spiked especially strongly after eating bananas.

That is very surprising. Even the macronutrient source independent of caloric content can cause changes in blood sugar. That is a very interesting finding. So we would choose our calories wisely. It might explain something that happens to me after I have been fasting. I will start feeling fatigued and by far the best pick me is eating an orange. The effect is immediate. Perhaps that explains why I have always loved oranges.