My experience with nuts guided me on to find related effects in other foods, which I will detail in due course.

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But first, I want to skip ahead to a remarkable discovery I made while reading various books and papers on the digestive system. I say a remarkable discovery–I mean a remarkable discovery for me. To be honest, the news that hit me between the eyebrows like a flying flowerpot is common knowledge in the gastrointestinal literature–which, after all, is not aimed at dieters.

So when I followed the trail of nuts into the labyrinth of digestive science, I sniffed out the following fact––which is undisputed: humans naturally excrete a percentage of the calories not just in nuts but in many common foods. The percentage starts at about 5% and may rise significantly higher in some foods for some people (we vary markedly as digesters). With this knowledge, it struck me that dieters and maintainers might, after a little experimentation, be able to eat more of certain foods than they thought they could–in fact, they might be able to eat more food altogether. That is my hypothesis, anyway.

I feel nervous even proposing it. And therefore obliged to quote some of the information I came across, lest I sound a crackpot. (I don’t think I’m a crackpot––but I admit that it’s an odd man who reads about the gastrointestinal tract over breakfast as others might read the newspaper.) So here’s a selection of remarks I noted down (they may not all be word for word):

“Some fibres, in particular the more soluble, fermentable fibres from fruit and vegetables, reduce the overall absorption of fat and protein … In one study, subjects eating a low-fibre diet had an 8% higher absorption of energy from food than subjects eating a high-fibre diet.” (Howarth et al, Dietary fibre and weight regulation, 2001.)

“Fibre may affect the digestibility of other components of the diet, since fat and nitrogen excretion have been shown to increase with high-fibre intakes.” (J H Cummings, Progress Report: Dietary Fibre, 1973)

“Calorific value may not simply be additive metabolizable energy from fat, protein, and carbohydrate provided by factorial equations but may be a function of the interaction of these nutrients with dietary fibre. This is not taken into account in food labelling.” (Baer et al, Dietary fibre decreases the metabolizable energy content and nutrient digestibility of mixed diets fed to humans, 1997)

“The effect of the unavailable carbohydrates on the apparent digestibility of the other energy-yielding constituents of the diet implies that the use of a single series of energy-conversion factors for calculating the metabolizable energy of a diet from its composition may lead to an overestimation if the diet is rich in unavailable carbohydrates.” (Southgate, Fibre and the other unavailable carbohydrates and their effects on the energy value of the diet, 1973)

“Fibre has been recognised as a satiety factor for some time, but it also decreases energy intake by reducing the efficiency of energy absorption.” (Coulston and Boushey, Nutrition and the Prevention and Treatment of Disease, 2008)

“Soluble viscogenic material can dissolve and disperse through the aqueous phase, inhibiting both the solution and the diffusion of a soluble nutrient. Further, the presence and persistence of intracellular or extracellular structures that envelop or otherwise sequester particulate nutrients may impair their solution, digestion, and absorption.” (Lentle and Janssen, The Physical Processes of Digestion, 2011)

“[…] dietary fibre could provide a mechanical barrier to the enzymatic digestion of other macronutrients such as fat and starch in the small intestine.” (Huaidong Du et al, Dietary fibre and subsequent changes in body weight and waist circumference in European men and women, 2010)

“[…] the slow rate of digestion of legumes may be related to the entrapment of starch in fibrous thick-walled cells, which prevents its complete swelling during cooking. In addition, resistance of starch to pancreatic hydrolysis may result from the presence of intact cell walls, which survive processing and cooking and insulate starch in such a manner that portions of it cannot be digested or absorbed.” (FAO/WHO Report, Carbohydrates in Human Nutrition, 1998)

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Apologies for the repetitive nature of the quotes; but if I’m to pursue the ambitious notion that dieters and maintainers could eat more food than they do, I have to show that my starting point is more than a beautiful dream.

And just as I promised this was not going to be all about nuts, I’ll add that it’s not going to be all about fibre either. Starch, as those last two quotes suggest, can make it to the lower intestine as well–as can other resistant nutrients. Meat too has a role in weight regulation (yay, a conventional low-carb statement at last!).

Nothing a healthy body does is an accident. If it sees fit to block the digestion and absorption of certain calories, I'm sure it does so for a purpose.