I’m not a particularly enthusiastic advocate of legumes on account on their tendency to cause digestive symptoms (such as bloating and wind), but I do believe they can be included in moderation in the diet as a potential substitute for grains and as an ingredient in, say, soups and stews.
What to Eat?
A diet that does not feature grains leaves fruit and vegetables as our main sources of carbohydrate. You may actually quite like spinach and broccoli and the odd piece of fruit, but the thought of subsisting on these sorts of foods for long periods is unlikely to appeal much.
Don’t lose heart yet, though, as there are plenty of foods that we have not even touched on yet, because they contain little sugar or starch, and therefore cannot disrupt blood sugar levels to any significant degree. These foods, which are primarily composed of protein and/or fat, include meat, fish, eggs, nuts and seeds. So, if we were thinking of eating a diet with the express purpose of stabilizing blood sugar levels and keeping insulin levels in check too, then these foods, accompanied by some vegetables and perhaps some fruit, will fit the bill.
The final part of this chapter provides instruction on what this sort of diet looks like in terms of easily sourced and practical meals and snacks. However, it may have occurred to you that foods such as red meat and eggs may be fine from a blood sugar balance perspective, but will only lead us down a ruinous path to heart disease and premature death. In Part 2 of this chapter, we’re going to explore this idea, as well as how we might eat to optimize our health and wellbeing in the long term.
PART 2: EATING TO LIVE
In this second part of the chapter, we’re going to use science and published research to determine the best foods for sustaining ourselves long into the future. Just for a moment, though, let’s step away from the science and introduce some old-fashioned common sense. At the beginning of this chapter, I promised you I would reveal a way of thinking about food that allows us to make quick, accurate and future-proof decisions about the best foods to eat. So what is it?
What’s the Big Idea?
What should be the best diet for us humans? The answer, theoretically at least, is one based on the foods we’ve been eating the longest during our time on this planet. These are the foods we evolved to eat, after all, and are therefore those that we’re the best adapted to. It’s these foods, evolutionary biology dictates, that will likely suit our innate physiology and biochemistry the best, as well as our nutritional needs. Relative nutritional newcomers, on the other hand, are more likely to create a ‘mismatch’ with the natural order within us, and therefore compromise our wellbeing and health over time.
Evolutionists generally agree that our first truly human ancestors emerged about two and a half million years ago in Africa. From there, our earliest forefathers are believed to have made their way into colder regions lacking much in the way of edible vegetation, making meat-eating a necessity for survival. Direct evidence for meat-eating comes from patterns of wear and tear in the teeth of our early ancestors,16 as well as the discovery of stone tools and bones scored by cut marks which indicate that butchering of meat went on some two million years ago.17
Things changed when our ancestors began to settle in communities and cultivate grain crops such as wheat and corn. But when did this happen? The palaeolithic record tells us that agriculture began only 10,000 years ago. That sounds like a long time ago, but is it really in the context of the whole of human evolution?
One way to get a good overview of the timing of the addition of grains to the human diet is to imagine our evolution spread out over the course of a calendar year, with the first origins of human life starting on 1 January, stretching to the present day at midnight on 31 December. According to this scale, we were exclusive hunter-gatherers from 1 January until about midnight on 30 December. It was only on the last day of the year that we added grains to our diet.
Genetic change is generally a very slow process, and our genes have altered only a fraction over the last 10,000 years. In this context, one could rationalize that perhaps, theoretically at least, grains do not represent ideal foods for human consumption. But it’s not just a theory, because we’ve seen how grains are often highly disruptive to the body’s chemistry, and can contain substances such as phytates, lectins and gluten that pose other hazards for our health.
Actually, we have evidence from the very dawn of civilization that grains were not the best way to go from a nutritional perspective. For example, the addition of these foods into the diet was accompanied by a significant deterioration in our dental health18 and led to a sudden drop in height of some 4–6 inches.19
What On Earth Did We Eat?
We cannot know for sure what our oldest ancestors ate prior to the invention of agriculture, and this no doubt would also have varied quite a bit according to geography: individuals from colder climes would generally have had to rely more on hunted and fished foods than those living in warmer parts of the world where edible fruits and vegetables were more abundant.
One way to get a more precise picture of our ancestral diet is by looking at the diets of traditional, modern-day hunter-gatherers. When this has been done, it turns out that the percentage of calories coming from hunted and fished foods ranges from about 50 per cent in, say, areas of tropical grassland, to about 90 per cent in the cold and relatively barren tundra.20 Also, in this research of over 200 hunter-gatherer populations, not one was found to be vegetarian.
It seems that flesh foods, including red meat, are a fundamental part of the human diet. Yet we are usually warned off red meat, as well as another ‘primal’ animal food – eggs. The case against these foods is based on the fact that they are rich in cholesterol and so-called ‘saturated fat’, which are said to ‘clog the arteries’. Saturated fat, along with other fats, is also said to be inherently fattening.
While red meat and eggs have been some of the most vilified foods of all, wouldn’t evolutionary theory suggest that there is little to be concerned about here? Either this concept holds true, or these foods are genuinely unhealthy: it can’t be both. So, which is it?
As we did with carbohydrate, let’s assess the impact of dietary fats and cholesterol on health using science and published research.
Is Fat Fattening?
Conventional wisdom tells us that weight gain follows when we consume more calories than the ones we metabolize. A gram of fat contains about twice as many calories as either carbohydrate or protein. So, logic dictates that the more fat we eat, the more likely we are to consume calories that are surplus to our requirements, which then end up being stored as fat in our bodies. Another thing that adds to dietary fat’s fattening reputation is its name (it is called fat, after all).
These facts do, on the face of it, seem to incriminate dietary fat as something inherently fattening, and appear to justify a somewhat joyless life replete with low-fat foods and an absence of butter and bacon.
However, the propensity for fat to be stored in the body is not purely determined by the balance of calories going into and out of the body, but also by the impact foods have on hormones that regulate weight. A key player here, as we learned earlier, is insulin. Insulin is secreted readily in response to glucose (from sugar and starch in the diet), but dietary fat has minimal, if any, insulin-inducing effects. In theory at least, this means that fat has limited fattening potential.
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