Observations from France

I recently got back from a trip to the UK and France visiting family and friends. It was great to see everyone, eat great food and even do some unexpected foraging (chestnuts, mushrooms, walnuts, blackberries). French people are in better general health than most industrialized nations. The obesity, diabetes and heart disease rates are all considerably lower than in the US, although still much higher than in non-industrial cultures. Here are a few of my observations about French food:

1. The French diet generally contains a lot of fat, mostly from traditional animal sources such as dairy and pork fat. Industrial seed oils have crept into the diet over the course of the 20th century, although not to the same degree as in most affluent nations. People seem to think that eating a lot of fat is unhealthy, particularly the younger generation, but they do it anyway. I had dinner with my family at a traditional restaurant in Lyon (a "bouchon Lyonnais" called Stepharo) last week. Before we ordered, they immediately brought out crispy fried chunks of pork skin and fat (I'm not claiming this is healthy!). The entree was a salad: a bed of lettuce piled high with chicken livers, herring, and "pig's feet". The pigs feet were essentially gobs of pork fat. It was a very good meal that I'll continue describing later in the post. I think it's worth pointing out that Lyon is in Southern France. Is this the "Mediterranean diet"?
   
2. French people eat organs. Yes, they never got the memo that muscle meat is the only edible tissue. A typical butcher or even grocery store will have liver, tripe, kidney and blood sausage on full display next to the meat. If you want to make a French person angry, try selling them a chicken or a rabbit without the liver, gizzard and heart. The main course at Stepharo was a large "andouilette", or tripe sausage, baked in mustard sauce. This was a typical traditional restaurant, not a hangout for gastronauts.
   
3. French people fiercely defend the quality of their food. Have you heard of the abbreviation AOC? It stands for "Appellation d’Origine Contrôlée", or controlled designation of origin. A familiar example is Champagne, which has the AOC label. You can't call your sparkling wine Champagne unless it comes from the region Champagne. However, that's only half the story. AOC also designates a specific, traditional production method, in this case called the "méthode champenoise." The AOC label can apply to a variety of food products, including wine, butter, cheese, honey, mustard and seafood, and is a guarantee of quality and tradition. 44 cheeses currently have the AOC designation, and these are commonly available in markets and grocery stores throughout the country (1). These are not fancy products that only the wealthy can afford-- many of them are quality foods that are accessible to nearly everyone. AOC defines many aspects of cheese production, often requiring a minimum amount of pasture time and specifying livestock breeds. The US has a few products that are regulated in a similar fashion, such as Bourbon whiskey, but generally we are far behind in assuring food quality and transparency.
4. French people cook. There is less outsourcing of food processing in France, for several reasons. One reason is that restaurants are generally expensive. That trend is changing however.

I don't think the French diet is optimal by any means. They eat a lot of white flour, some sugar, seed oils and other processed foods. But I do think the French diet has many good qualities, and it certainly poses a number of problems for the mainstream concept of healthy food. Hence the "French paradox."

Obesity and the Brain

Nature Genetics just published a paper that caught my interest (1). Investigators reviewed the studies that have attempted to determine associations between genetic variants and common obesity (as judged by body mass index or BMI). In other words, they looked for "genes" that are suspected to make people fat.

There are a number of gene variants that associate with an increased or decreased risk of obesity. These fall into two categories: rare single-gene mutations that cause dramatic obesity, and common variants that are estimated to have a very small impact on body fatness. The former category cannot account for common obesity because it is far too rare, and the latter probably cannot account for it either because it has too little impact*. Genetics can't explain the fact that there were half as many obese people in the US 40 years ago. Here's a wise quote from the obesity researcher Dr. David L. Katz, quoted from an interview about the study (2):

Let us by all means study our genes, and their associations with our various shapes and sizes... But let's not let it distract us from the fact that our genes have not changed to account for the modern advent of epidemic obesity -- our environments and lifestyles have.

Exactly. So I don't usually pay much attention to "obesity genes", although I do think genetics contributes to how a body reacts to an unnatural diet/lifestyle. However, the first part of his statement is important too. Studying these types of associations can give us insights into the biological mechanisms of obesity when we ask the question "what do these genes do?" The processes these genes participate in should be the same processes that are most important in regulating fat mass.

So, what do the genes do? Of those that have a known function, nearly all of them act in the brain, and most act in known body fat regulation circuits in the hypothalamus (a brain region). The brain is the master regulator of body fat mass. It's also the master regulator of nearly all large-scale homeostatic systems in the body, including the endocrine (hormone) system. Now you know why I study the neurobiology of obesity.


* The authors estimated that "together, the 32 confirmed BMI loci explained 1.45% of the inter-individual variation in BMI." In other words, even if you were unlucky enough to inherit the 'fat' version of all 32 genes, which is exceedingly unlikely, you would only have a slightly higher risk of obesity than the general population.