Team McCallum

R&D for Lifetime of Life

Udiet: the battlefield.

2010 was stuffed with debate over the reasons why people in developed countries are getting heavier.

 The most simplistic explanations focussed on overeating, or inactivity, or both. HFCS (high fructose corn syrup) also came in for a beating. The problem with this is that Europe imports very little HFCS, but countries in Europe are reporting more and more problems associated with obesity.

 www.obesitymyths.com comes up with a much larger range of interesting possibilities. But in 2005, the New York Times linked this site to sponsorship from fast food producers such as Coca-Cola and McDonald’s, in this article.

Two reputable groups of scientists published work where they found that the mantra of ‘eat less and exercise more’ doesn’t cover all of the potential reasons.

 A government group in the UK called Foresight was asked to predict what will happen there over time, based on best evidence, and building in realistic assumptions. In order to do so, they had to scour published research to identify the drivers of obesity and build a very detailed model of which drivers are most important. Written in simple English, this is probably the best explanation there is of the obesity epidemic.

The full report is available as a free PDF download here. However, at over 160 pages, it won’t be everyone’s cup of tea.

The second group of scientists published a summary of obesity drivers in November 2009. Again, this is available free using this link.

Their findings outline the battlefield for the Udiet.

1. Overeating, particularly re heavily marketed energy dense foods.

2. Underactivity, again with an organisation driver behind it.

3. Infection caused by bacteria and viruses.

4. Epigenetics, whereby prenatal and early postnatal exposure to the environment alters how genes are expressed without changing the genes. For example, babies born very underweight at birth who are incubated and fed rich diets to catch up weight have a higher risk of obesity and associated issues later in life.

5. Increasing maternal age. Animal studies have shown that babies born to older mothers are fatter than those born to younger mothers.

6. BMI breeding effect. Studies have found that those with a body mass index somewhat above average are producing slightly more children, on average, than the rest of the population, causing the population BMI to increase over time.

7. Assortitative mating is taking place. This hypothesis is that those with higher BMI prefer partners of similar kind, and due to the genetic effect, this leads to even heavier children. A wide range of population studies support this idea.

8. Sleep debt is happening, and leads to increased eating, increased fat deposition and lowered activity. Research shows metabolic changes occur to support this, and also leads to higher risk of diabetes and heart disease. For example, one study shows that getting one and a half hours less sleep than ideal over a two week period results in a diabetic-like profile for glucose and insulin.

9. Endocrine disruptors interfere with estrogen and androgen signalling, and have been building up in the human environment for some time.  These have been found to be involved in obesity in animals and in humans.

10. Commonly used medicines are known to contribute to weight gain. These include medicines for diabetes, high blood pressure, steroids, contraceptives, and anti-histamines.

11. Artificial ambient temperature. The hotter your environment, the less energy you burn keeping warm. The UK home went from 13 centigrade in 1970 to 18 centigrade by 2000. US homes went from 18 centigrade in 1923 to nearly 25 centigrade in 1986.

12. Mothers input. The state of the mother’s glucose and insulin handling systems directly affect the number of fat cells and the fat cell content of the baby.

13. Reduction in smoking rate. The scientists considered this so well documented they excluded it from their list.

14. Altered US demographics. A 2006 article along the same lines had found that alterations in the US population were increasing the races which tend toward higher BMI, therefore  increasing the average BMI of the nation.

The aim of the scientists’ report was not to remove the first two reasons from focus, but to show that the battlefield is considerably more complex than simply food and exercise.

These 14 points are not comprehensive. For example, other researchers have found that altering the circadian rhythm, by staying up late in artificial light and not synchronising your body clock to early morning light, is also a risk factor for weight gain. Also, breastfeeding v formula milk wasn’t mentioned, although formula milk is associated with higher risk of obesity.

January 9, 2011 Posted by | Activity, BMI - body mass index, Breastfeeding, Child Health, CVD - cardiovascular disease, Diabetes, Environment, Epigenetics, Exercise, HFCS - high-fructose corn syrup, High blood pressure, Obesity, Pregnancy, Pregnancy, Success, Thermogenesis, UK, United States, Weight management | Leave a comment

Boys and 0-6 months.

In boys, better nutrition in the first 6 months of life is linked to adult features of greater height, more muscle mass, better grip strength and higher testosterone, but not disease characteristics. Girls did not show a link between height, strength and early nutrition.

Prof Christopher W Kuzawa analysed results from 770 Filipino males aged around 22 who have been followed from birth.

Those gaining weight the fastest in the first 6 months were, typically, breastfed and lived in wealthier households with better hygiene.

Prof Kuzawa considers the result is the effect of changes in links between the brain (hypothalamus), pituitary gland and gonads, as this circuit is sensitive to environmental factors during this period.

According to Kuzawa “Male infants in the first six months of life produce testosterone at approximately the same level as an adult male.”

The effect of better feeding is to launch the child on a strategy of high reproduction, as for these people the age of first sex was earlier, the men reported more sexual partners, and more had had sex in the last month.

September 15, 2010 Posted by | Brain, Breastfeeding, Christopher W Kuzawa, Gender, Success | Leave a comment

Breast milk v formula.

Prof Sharon Donovan studied the genes expressed in the intestines of babies fed either breast milk or formula in the first 3 months of life.

“For the first time, we can see that breast milk induces genetic pathways that are quite different from those in formula-fed infants. Although formula makers have tried to develop a product that’s as much like breast milk as possible, hundreds of genes were expressed differently in the breast-fed and formula-fed groups.”

Many of the differences found by the scientists were in fundamental genes that regulate the development of the intestine and provide immune defence for the infant.

Donovan also would like to learn how bacteria in the gut differ in these babies. “Now we’ll be able to get a complete picture of what’s happening in an infant, from the composition of the diet to the microbes in the gut and the genes that are activated along the way.”

May 13, 2010 Posted by | Breastfeeding, Child Health, Genetics, Science, Sharon Donovan, Success | Leave a comment

Hormone link to breastfeeding

Researchers from the Norwegian University of Science and Technology have reported that ability to breastfeed is linked to testosterone level in the mother.  Low rates of breastfeeding at 3 and 6 months were linked to high testosterone in the womb.

The team suggest that the hormone may impact negatively on the development of glandular tissue in the breast, in turn affecting a mother’s ability to feed her baby.

Lead researcher Professor Sven Carlsen argues that hormone balance in the womb explains both ability to breastfeed and any apparent health benefits rather than the breast milk itself. 

The study appears in Acta Obstetricia and Gynacologica Scandinavica.

January 7, 2010 Posted by | Breastfeeding, Child Health, Sven Carlsen | Leave a comment