To understand this conundrum, we first have to understand how calories are formed.

We have come to think of calories as little packets of energy somehow embedded in our food.

However, they are not real, they are simply a measure of how much heat is given off when foods are burned.

So what relationship does burning food in a furnace have to what happens to food in our bodies? Interestingly, not a single scientific study has been carried out to answer such an obvious question – and for obvious reasons, it is just not feasible.

Digesting and assimilating food energy is a complex biological process that is impossible to replicate using laboratory equipment, especially a crude 19th century device like a bomb calorimeter.

Nuts are a good example (before we get to alcohol). They are full of fats and oils, are among the top 10 most calorific foods and are recommended to people who are dangerously underweight.

They are also superfoods that can help heart health. In the last 20 years, consistent studies have shown that nuts not only do not put on weight, they may even help reduce it.

Nutritionists have tried to explain this by stating that they make you feel full, so you eat less food. However, at least two studies have shown that this can’t be the complete answer.

In a study where people were fed diets with identical calories, they put on less weight when the diet contained nuts (Am. J. Nutr., 2003).

Additionally, there is no evidence that alcohol itself adds weight. Again, as with nuts, alcohol contains plenty of calories, almost as much as fat. However, the fact remains that alcohol is not fattening. In the late 1990s, researchers from Brigham and Women’s Hospital in Boston, Massachusetts, embarked on a survey of around 20,000 middle-aged women, whose drinking habits and weights were tracked for almost 13 years.

At the beginning of the study, all the women started out with low to medium weight (roughly dress sizes 8 to 12). By the end of the survey period, around 9,000 women had put on significant amounts of weight and some even became clinically obese.

Conventionally, medical theory would dictate that all those who had put on the most weight would be the ones most likely to be drinking larger amounts of alcohol.

However, the reverse was true. The fattest women were the ones who didn’t drink and the thinnest women were the heaviest drinkers. In this study, it was the women who didn’t drink who turned into a size 18 not the women who drank volumes. (Arch. Intern. Med., 2010).

There are at least a dozen other studies of alcohol and weight that confirm the findings of this study. There is a major caveat with these findings. The study does not conclusively show that alcohol does not add weight. The data shows only a correlation between alcohol and weight.

There are many theories to try to explain this conundrum. Sceptical nutritionists will say that alcohol is making people eat less, meaning they are substituting food calories for alcohol calories.

This theory was tested in 1999 by Dutch physiologists at Maastricht University who tested 52 people to see if the sceptics were right. Predictably, they weren’t. Alcohol actually made people eat more (Am. J. Clin. Nutr., 1999). There are so many other theories, including one that looks at the calories themselves.

This is not a flag to go out and drink to stay slim. Alcohol, like cigarettes, has very damaging side effects to our long-term health

When someone cuts down on food to lose weight, they usually cut down on carbs. However, the carbohydrate content of drinks is very low despite their calorie content being high.

Spirits don’t contain any fat, carbs or protein. However, they have a massive calorie score. Could it be then that the past system of counting calories is to blame?

There is a very interesting background to how calories came about, ostensibly from the idea of a 19th century French engineer/scientist.

Nicolas Clement-Desormes wanted to find an accurate measure of heat energy. He abandoned his concept in 1880, only for it to be taken up by an American agricultural chemist, Wilbur Atwater, whose motivation was the poverty of the common people.

He wanted to determine which foods gave the most energy for the lowest cost, so he could recommend the cheapest foodstuffs to be eaten by the US’s labouring classes to fuel their toiling muscles. He stole Clement’s ‘steam engine calorie’ idea and turned it into a ‘food calorie’ concept.

This is where burning calories relates to food and a furnace, as mentioned earlier.

Atwater’s theory of burning food was the basis of calories as we know them today. It tells you nothing of what happens to food in the body.

Burning one gram of coal creates almost 10 times the amount of heat as burning one gram of fat, but we don’t say that coal contains 70 calories and that you will increase your weight if you eat it.

That is what happens when a 19th century engineer’s theories are taken up by an agricultural chemist. The problem is that these theories underpin modern nutritional science.

So post-Atwater nutritional science went on to claim that if you ingest calorie energy but don’t use it up in running the body’s processes, the leftover calories will be deposited as fat.

This is a fascinating subject. More can be read in The Good News About Booze, by Tony Edwards.

However, this is purely thought-provoking and not a flag to go out and drink to stay slim. Alcohol, like cigarettes, has very damaging side effects to our long-term health.

kathryn@maltanet.net