I plan to make this the first of an occasional (for which read ‘when I can be bothered’) series on poor science journalism. Let’s look at this slow-news-day article from the BBC News website, entitled “Alcohol calories ‘too often ignored’”. All quotes are from that article. I’m going to presume there was some scientific research behind the story, though in reality I suspect this is a regurgitated press-release for a hung-over second of January deadline.
People watching their weight should pay closer attention to how much alcohol they drink
No argument yet, but then:
since it is second only to fat in terms of calorie content, say experts.
Hang on a second. Can it be really true that a drinker’s main source of calorific content is fat, and second alcohol? The recommend daily intake for fat is about 65g per day for an adult, as opposed to around 300g of carbohydrate and 50g of protein. As fat yields about 9 kcal/g, ethanol 7 kcal/g, and carbohydrates around 4kcal/g, it’s pretty obvious a normal adult will in fact derive most of their calorific intake from carbohydrates. Perhaps they mean ‘second most calorific content per gram’? Well, that too would be misleading as people neither eat raw fat nor drink raw alcohol. Weight for weight, a most food is going to contribute more calories per hundred grams than a drink, simply because most of your drink is water which has no calorific content. 100g of doughnut is going to be between 250kcal and 350kcal. 100g of apple is going to be about 50kcal. 100g (i.e. approx 100ml) of red wine is going to be about 68kcal. And 100g of beer is going to be about 32kcal; clearly on this basis we should all be drinking beer rather than eating apples. Of course they could have written “Ethanol delivers more kilocalories per gram than any macronutrient other than fat”, but that would have revealed why the statement is largely specious.
According to the World Cancer Research Fund, alcohol makes up nearly 10% of total calorie intake among drinkers.
This certainly can’t be true for every person who drinks. I find that statement surprising, particularly if averaged across everyone who drinks. Without the definition of what a ‘drinker’ is, or whether this is a mean or a median, this statement is meaningless.
Having a large glass of wine will cost you the same 178 calories as eating two chocolate digestive biscuits.
Firstly, neither food costs you calories. Going for a run costs you calories, as you expend calories running. Eating and drinking gains you calories.
Secondly, if I believed this article, these chocolate biscuits are going to be very tiny, as “Protein and carbohydrates contain 4kcal/g and fibre 2kcal/g.” (as it says later), hence the chocolate biscuits must weigh less than a gram – impressive dieting! Of course what they’ve done here is confused Calories and kcal. A Calorie (normally written with a capital ‘C’, and abbreviated ‘Cal’) means a kilocalorie, i.e. 1,000 calories (small ‘c’, gram calories). Yes, it’s confusing (which isn’t the journalist’s fault) but using ‘kcal’ and ‘calorie’ within the same article is an artificial distinction that is going to lead the reader to think ‘but the author must mean something different by the terms, so the first is 1,000 times the second’.
Eating or drinking too many calories on a regular basis can lead to weight gain. But unlike food, alcoholic drinks have very little or no nutritional value.
Now I’m very confused. How can we gain energy (and thus weight) from alcoholic drinks (which often contain sugar as well as alcohol), but the drink have ‘no nutritional value’? The nutritional value of food is the quantity and type of macronutrients (water, carbohydrate, fat and protein), and micronutrients (vitamins, minerals, and possibly some other bits and bobs) found within the food. Clearly alcoholic drunks have nutritional value as they contain water, sugar and ethanol which (as the author has already pointed out) has high calorific content. Let’s also ignore all the previous articles about antioxidants in wine (those would fall into the ‘bits and bobs’ category). Certainly it would be a bad plan to obtain the majority of your nutrition from alcoholic drinks. I would suggest the main danger would be to your liver. To my knowledge, not many alcoholics die of malnutrition.
The ‘empty calories’ in drinks are often forgotten or ignored by dieters, says the WCRF.
I bet they didn’t say that, at least not without defining ‘empty calories’. Without the word ‘empty’, this sentence would make sense.
Kate Mendoza, head of health information at WCRF, said: “Recent reports have shown that people are unaware of calories in drinks and don’t include them when calculating their daily consumption.”
Ah, some sense at last. Did you notice that this, along with another quote from Ms Mendoza which also makes sense, were the only parts of the article written by WCRF rather than the journalist? Unfortunately, access to the remainder of Ms Mendoza’s wisdom is prohibited by a lack of a link to the original research publication (we wouldn’t want the public to be educated after all), and the fact that WCRF’s web site is appallingly slow.
The scientific component of the story in whole consists of ‘people who drink alcoholic drinks regularly often forget that the drinks have a significant calorific value’ (drink enough and you’ll forget other things too). As this is no more counterintuitive than the defecatory habitats of the Ursidae, the text must then end with some standard padding about safe drinking with no relevance to this at all.
You would have thought the BBC could do better than this example of sloppy journalism, but all too often science journalism is pretty awful.