A nutrition paradox

By denying scientific principles, one may maintain any paradox. 

                                                                                Galileo Galilei

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If an overweight person wishes to slim down, the most effective way of doing so is undeniably to live on a diet consisting mainly of fat and protein, even without concern for energy intake. The logic is simple. The two factors mostly in charge of fat cell hypertrophy, glucose and insulin, are mainly influenced by dietary carbohydrates. Scientific data support this.

The very same diet is according to an ever increasing pile of high quality scientific data one of the healthiest diets we know of. This way of eating has been tested repeatedly and the grand total of our knowledge show us that this is in fact the diet which with the greatest probability is the most effective we know of for weight loss and health improvement in general.

This rather unpleasant fact is by some perceived as a paradox; that the very food we have been warned about for half a century because it makes us fat proves best at reducing weight. But is the observation that the main constituent of our diet has to be the most energy dense nutrient, if we wish to reduce our weight and stay slim, really a paradox?

The American paradox describes the current situation in the USA where both average energy intake and fat intake seems to have been declining during the very same time period where weight and waistlines have increased. 

There are many similar nutritional paradoxes like the American paradox. The French paradox is the observation that the French suffer a low incidence of coronary heart disease, despite having a diet relatively rich in saturated fats. Hyperlipid muses about these and other paradoxes here.

Professor of philosophy, Mark Sainsbury understands the paradox as, 

…an apparently unacceptable conclusion derived by apparently acceptable reasoning from apparently acceptable premises.

One of the best known paradoxes is the liar paradox. One version goes like this:

“What I am now saying is false.”

Is what he’s saying true or false? The problem is that if he is speaking the truth, then what he is saying truly is false, thus he is lying. But if he’s lying then what he is saying is the truth and so we continue going round and round.

Real paradoxes are rare, they are more linguistic peculiarities, and there are no real paradoxes in the natural sciences. Although the famous thought experiment of Schrödinger's cat is often described as a paradox, it is nothing but a thought experiment. In the real world we would just open the damn box and declare the cat either dead or alive.

A real logical paradox does not exist in natural science because the paradox requires two conflicting statements to both be true at the same time. Fat for example will not make us both fat and lean. Either fat cause overweight or it doesn’t. If the hypothesis claims that eating fat make us fat, yet scientific data show us otherwise, then it means the hypothesis is wrong. There is no need to go crying paradox.

The apparently unacceptable conclusion has not been derived from acceptable reasoning or acceptable premises. The conclusion that fat make us fat is unacceptable.

The scientific data supporting a claim that increasing fat intake cause decreasing weight are many and not easily discarded. Despite of this, the hypothesis claiming fat makes us fat is maintained despite its all too apparent inability to explain the current observations. In order to keep the hypothesis, a paradox is created. By crying paradox we relieve our self from the difficult task of discarding our dear hypothesis and at the same time we gracefully avoid the creation of new knowledge and scientific progress.

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In order for a hypothesis to be viable it has to be able to sufficiently explain the current observations. The hypothesis seeking to explain overweight through excess energy consumption mainly from fat cannot sufficiently explain the current observations and is therefore wrong. It has to be discarded.

Similarly, the hypothesis trying to explain overweight through lack of energy expended during physical activity also does not sufficiently explain the observations and must be discarded. Sainsbury puts it like this:

… generally we have a choice: either the conclusion is not really acceptable, or else the starting point, or the reasoning, has some non-obvious flaw.

What is so great about encountering paradoxes in natural sciences is that they simply do not exist. So when we’re faced with one we know our hypothesis must be modified or discarded. The scientific paradox offers a mental cold shower, but at the same time it gives us the opportunity to take one step closer to the truth.

In the world of health and nutrition science there are many more or less well known paradoxes all based on apparently acceptable reasoning from apparently acceptable premises, but which in reality are nothing but obvious facts concealed by at best poor and at worse completely false hypotheses.

Bad hypothesis example: The dog did it. Image from Istockphoto

Poor people and people with low social status seem to be more overweight than richer people in the same country or region. This means that the people with the least money and more often physical laborious work are the fattest. These findings do not go well with the hypothesis explaining overweight as a disease caused by the abundance of modern society.

In The Journal of the Norwegian Medical Association, Per Ole Iversen writes about the situation in South Africa where paradoxically one often observe undernourished children with overweigh mothers. This seems a common observation in poor and malnourished populations. Benjamin Caballero wrote in “A nutrition Paradox - Underweight and Obesity in Developing Countries”,

A few years ago, I was visiting a primary care clinic in the slums of São Paulo. The waiting room was full of mothers with thin, stunted young children, exhibiting the typical signs of chronic undernutrition. Their appearance, sadly, would surprise few who visit poor urban areas in the developing world.

He continues:

What might come as a surprise is that many of the mothers holding those undernourished infants were themselves overweight.

This is not a new observation although Caballero seems to think so, but he is right in that:

The coexistence of underweight and overweight poses a challenge to public health programs, since the aims of programs to reduce undernutrition are obviously in conflict with those for obesity prevention.

Caballero’s got an important point. Because if you accept the hypothesis claiming overweight is caused by high energy intake you also have to accept the implied notion, that these mothers are willing to watch their children starve for lack of food while they eat themselves fat.

By denying basic scientific principles, one takes part in the upholding of paradoxes. Paradoxes that hinder scientific progress and that in the case of overweight and obesity contribute to feelings of failure and disappointment when what people are told is the right way to loose weight just does not work.