Do Non-Exercising Chicken Promote Obesity in Humans?

Every now and then you come across a study on a seemingly bizarre topic that serves as an eye-opener on just how complex the factors leading to obesity can be.

This is certainly the case for a study by Yiqun Wang and colleagues from the London Metropolitan University, UK, just published in Public Health Nutrition, which comes to the astonishing conclusion that modern organic and broiler chickens sold for human consumption provide more energy from fat than from protein.

This is of significance, as all current nutrition guidelines list chicken together with fish as a healthy and recommended source of “lean” protein.

Wang and colleagues not only examined chicken samples purchased from supermarkets and farm shops in different locations across the south-east to the mid-west of England, but also looked at the historical reports on chicken meat protein and fat composition.

Interestingly, between 1870 and 2004, chicken fat content increased from around 4 g or 36 KCal/100 g to 23 or 207 KCal/100 g, an almost five-fold increase. During the same time period, chicken protein content decreased from 21 g or 84 KCal/100 g to 16 g or 64 KCal/100 g, an almost 25% decrease in energy from protein. As a result, the fat:protein energy ration increased from 0.4 to 3.2, an eight-fold increase.

Surprisingly, there was very little difference in fat content between battery-grown and “organic” chickens.

Not surprisingly, the authors conclude that, “While chicken was at one time a lean, low-fat food, it is no longer”.

What is perhaps also of interest is that while chicken were once perhaps one of the most important land-based sources of healthy long-chain n-3 fatty acids, the ratio of less healthy n-6 to n-3 fatty acids in modern chicken is now 9:1 (up from 2:1) – a development that the authors relate to a potential detrimental impact on brain development and mental health.

In fact, to obtain the same amount of docosahexaenoic acid (DHA) from intensively reared chickens today as would have been obtained in the 1970s, one would have to eat six chickens – ingesting somewhere in the region of 9000 kCal. (decreased intake of DHA has been linked to increased risk for Alzheimer’s and other mental disorders).

As to the underlying causes of these changes, the authors point to the following major changes in chicken husbandry:

1. Confining animals to enclosures in the 18th century.

2. Selecting those that gained weight fastest (they earned more at market).

3. The development of high-energy foods and growth promoters.

4. The restriction and final denial of exercise by keeping the animals in an enclosed space with food permanently available.

The authors note that, as in humans, the cocktail of gene selection for fast weight gain, lack of exercise and high-energy food available 24 hours a day, is a simple and well-understood recipe for obesity.

In the light of their data they raise the important question: “Does eating obesity cause obesity in the consumer?”

I’ve always wondered if there was a link between obesity in the English and their insatiable love for Chicken-Tikka-Masala? – now we know!

Edmonton, Alberta