Strangely, a feature of human bodies is that it is possible for a person to intake, digest and absorb a good supply of all the essential nutrients, and yet still not feel adequately fed. This shows up as a feeling of still being hungry, or of not feeling full or as an ill-defined drive to ingest food (often with the person not feeling what they would describe as “hungry”).
Similarly, it is possible for a person to have a plentiful supply of fuel energy coming into the body and stored in the body, and yet for that fuel energy to not flow properly and/or for the body to shift to a fuel-storage mode, leading to reduced metabolism, fatigue and so on.
There are two aspects to nutrition. One is to intake enough of all the vital nutrients to be able to meet your needs optimally. The second aspect is how your body handles those nutrients and whether they are all fully available for use as needed by all the different areas and cells of the body.
Essential Nutrient Nutrition has received the most focus over the past century and is a critically important part of health.
Now, Fuel Nutrition has come of age. The impact of problems with fuel intake signalling (appetite balance), fuel use and fuel storage has become a major player in today’s medical reality. Consider the impacts of obesity, metabolic syndrome, type 2 diabetes, and even the impact of the struggle people engage in to try to control their weight.
With so much at stake, can we afford to ignore the fact that how we handle our fuel flow and storage is not the same from person to person or even the same for one person over time? How our appetite balance systems work is not the same from person to person. Neither is how we respond to what we eat and when we eat.
General, population-level advice regarding food and nutrition is just not up to the task at hand. We are a few decades past the point when the vast majority of the population could be well served by an attempt to advise a theoretical “best diet”. For people who are “weight-reduced” (in other words, who have lost a significant amount of body weight – even, say, 5%), their appetite system is not working as it does in “normal” weight people who have never gained and lost a significant amount of weight. For people who have insulin resistance, metabolic syndrome or diabetes, their fuel flow pathways are not working “normally”.
With even just those examples, we already have more than half of the population, at least of western countries, who have appetite/fuel systems that are not functioning according to what we think of as the default normal function for humans. Some decades ago this was not true. Now it is a defining medical fact of our age.