Recent news reports encouraged me to take a quick look at the January 2010 American Journal of Clinical Nutrition where investigators have attempted to identify the proportion of human obesity accounted for by genetic variation.  Their conclusion: probably no more than 1% (we used to think it was 5%).  I don’t know why anyone would be surprised.  Obesity rates rose sharply in the early 1980s, with no possibility for so rapid a change in the genetic composition of the population.

I don’t think we need complicated genetic explanations for obesity.  We have so much evidence that people started consuming more calories at about that time and are continuing to do so.  Why more calories?  Portion sizes got bigger, and – hard as it may be to believe – larger portions have more calories!

In a commentary on the study, Claude Bouchard puts it this way:

The obesity epidemic we are facing today unfolded over the past few decades and can clearly not be explained by changes in the frequency of risk alleles. It is more likely due to a changing social and physical environment that encourages consumption and discourages expenditure of energy, behaviors that are poorly compatible with the genome that we have inherited.

Hence: eat less, move more!  And have an active weekend!

I feel like this will open a pandora’s box but I’m hearing more and more about food as a problem of addiction.  I have a hard time seeing it that way.  We have to eat to live and in that sense I suppose you could consider food addictive.  And food does stimulate the same pleasure centers that addictive drugs do, although not to the same extent.  But does that make food, and especially sugar, addictive?

Two studies take on the question.  The first, from Canadian researchers, equivocates.  In some ways yes, in other ways no.

The second study, from Wales professor David Benton, looks at what you would have to prove to prove sugar addiction and concludes that current observations just don’t support it.  He says:

If sugar addiction exists…addicts would experience increased food cravings, predominantly for sweet items; cravings would be especially strong in the morning, after an overnight fast; obese people would find sweet foods particularly attractive; and high sugar consumption would predispose people to obesity…There is no support from the human literature for the hypothesis that sucrose may be physically addictive or that addiction to sugar plays a role in eating disorders.  [Here’s the abstract of his paper]

Really?  I’m curious to know what’s out there on this.

For years, some people – not me – have been saying that eating one extra 50-calorie cookie a day can make you put on 5 pounds per year.  This calculation comes from basic math: if about 3500 extra calories make you put on a pound of body fat, then 50 times 365 is 18,250 extra calories which, divided by 3500,  equals about 5 pounds.

This never made sense to me.  It is impossible to know how much you are eating each day within 50 calories let alone how many calories you are using in daily activities.  Yet people used to be able to keep their weight steady without thinking about calories at all.

This is because the body regulates weight and can easily compensate for such small changes in calorie intake or output with small changes in metabolic rate.  It takes more calories to move heavier bodies, and fewer to move lighter ones.

For years, I’ve been thinking that it must take a lot more than 50 extra calories a day – I guessed hundreds –  to make people gain weight.  I thought this for two reasons:

First reason: Portion sizes have increased greatly in recent years, and larger portions have more calories.  Sometimes, they have a lot more.  Foods eaten outside the home often have more calories in them than anyone suspects.

That’s why calorie labeling matters.  Labeling may underestimate the actual calories present in a food according to Tufts researchers (see this week’s Time for commentary and also see the industry response).  But even so, a new study shows that labeling encourages people to cut down on food intake, at least at Starbucks.  Make that two new studies: one from the Rudd Center at Yale comes to the same conclusion.

Second reason: I keep hearing from pediatricians who treat overweight kids that they have kids in their practices who drink from 1,000 to 2,000 calories a day from sodas alone.  I can’t judge whether these figures are correct or not, but several different kinds of studies suggest that many people today are eating a lot more calories than their counterparts of 25 years ago.

Now Martin Katan and David Ludwig have done the actual calculations in a paper in this week’s JAMA titled “Extra calories cause weight gain–but how much?”  Their conservative estimate is that it would take an excess of 370 calories to gain 35 pounds in 28 years.   To become obese in 25 years, you would need to eat 680 calories a day more than you expended.

To become 58 pounds overweight at age 17, they predict that a child would need to overconsume 700 to 1,000 calories a day from the age of 5 or so.

These figures are quite consistent with what those pediatricians were telling me.  By other estimates, average caloric intake has increased by 200-500 calories a day since the early 1980s, along with a 700 calorie-a-day rise in the availability of energy in the food supply (from 3,200 to 3,900 per day per capita).

As Katan and Ludwig conclude:

small changes in lifestyle would have a minor effect on obesity prevention.  Walking an extra mile a day expends, roughly an additional 60 kcal compared with resting – equal to the energy in a small cookie.  Physiological considerations suggest that the apparent energy imbalance for much of the US population is 5- to 10-fold greater, far beyond the ability of most individuals to address on a personal level.  Rather, an effective public health approach to obesity prevention will require fundamental changes in the food supply and the social infrastructure.

This is because on the personal level, prevention of weight gain means eating hundreds of calories a day less.  Moving more, useful as it is, will not do the trick unless people eat less as well.

On the societal level, we need measures to make it easier for people to eat less.

I can think of a bunch of examples.  You?

I thought we were finished with melamine by now, but no such luck.   Recall that we first encountered Chinese melamine (ordinarily a benign component of plastic dinnerware and countertops) as a toxic adulterant of pet food in 2007.  Melamine, it turned out, had been used for decades to boost the apparent – not actual – protein content of foods and ingredients.  It is high in nitrogen and the test for protein in foods measures nitrogen, not protein itself.

In the wake of the pet food scandal, China cracked down on food safety violations.  That did not stop use of melamine and within just a few months, it turned up in infant formula and caused a reported 300,000 Chinese babies to develop kidney problems.  Chinese authorities again dealt harshly with perpetrators, executing some and giving others long prison sentences (to catch up with this story, see previous posts).

And now here we go again, and with one of the same companies implicated in the 2008 infant formula problem – Shanghai Panda Dairy Company.  Chinese authorities are again cracking down but, as the New York Times reports, the problem seems intractable.

Why?  Maybe Chinese adulterators are getting a double message.  Here are a couple of items I picked up off Chinese news sources on the Internet (Google the names to find the sites):

• Li Changjiang, the director of the inspection agency that failed to deal with the melamine problem, was forced to resign from the agency. He has overcome his disgrace, more or less.  He was just appointed deputy head of a major anti-pornography group.
• Zhao Lianhai organized the parents of victims of the infant formula adulteration to try to get compensation.  He was put under house arrest in November and formally arrested in December.

Melamine is an enormous embarrassment to the Chinese and they will get a grip on it eventually, but let’s hope sooner rather than later.  In the meantime, best to avoid food products made in China that are supposed to contain protein from milk or soybeans.

Update January 6: today’s Wall Street Journal reports that Chinese authorities have known about the melamine in milk:

Tuesday, the newspaper 21st Century Business Herald reported industry participants were aware of melamine use by Shanghai Panda as early as April 2009. The paper, which didn’t identify its sources, said that in November China’s minister of health, Chen Zhu, referred to melamine tainting by the company during an internal meeting of Communist Party officials. Those comments, the newspaper reported, prompted Wenzhou-based Zhejiang Panda Dairy Products Co. in early December to announce on its Web site that, while its name was similar to Shagnhai Panda, the two companies aren’t related.

I am trying to understand what to think about food nanotechnology and whether it is good, bad, or indifferent.  Nanotechnology refers to the use of very small particles for doing any number of things to food.  I’ve been collecting items about it:

• A recent review of the use of nanotechnology concluded that it has many possible benefits in improving the nutritional quality of foods.
• Nanotech particles from corn act as antioxidant emulsifiers.
• Nanotech particles enhance the bioavailability of beneficial plant chemicals.

But what about their safety?  Could nanoparticles cross cell-membranes and end up being harmful?  The technology to produce the particles does not cost much.  This means anyone can make and use them, including food manufacturers who don’t want to bother with safety testing.  So: is nanotechnology the new asbestos?

If you know something about this, please weigh in.  Thanks and happy new year!

Update, January 8: A the U.K. House of Lords Science and Technology committee warns that the lack of transparency in research on nanotechnology is likely to induce a consumer backlash similar to that on genetically modified foods.  Indeed.

My San Francisco Chronicle column, now appearing in print on the first Sunday of the month, is also online.

Its title:  “Hot food issues ready to boil over this year.”

Q: What do you think will happen with food and nutrition in 2010?

A: I wish I could read the leaves while I drink tea, but the best I can do is tell you which issues I’m going to be watching closely this year.

Hunter Public Relations recently asked 1,000 Americans which food-related issues they thought were most important in 2009. The top three? Food safety, hunger and food prices. For the decade, the winner was childhood obesity.

I have my own top 10 list of hot-button issues for 2010, and here they are:

• Hunger: More than 35 million Americans get benefits to which they are entitled under the Supplemental Nutrition Assistance Program (formerly, food stamps). The economy may be improving, but not quickly enough for millions who have lost jobs, health care and housing. Will Congress do anything this year to strengthen the safety net for the poor? It needs to.
• Childhood obesity: Rates of childhood obesity may have stabilized, but we all want to figure out how to prevent kids from gaining so much weight that they develop adult chronic diseases. I expect to see more efforts to improve school food and make neighborhoods more conducive to walking to school, riding bikes and playing outside.
• Food safety regulation: Congress is sitting on a bill to give the Food and Drug Administration some real authority for food safety. The bill does not do what is most needed – establish a single food-safety agency – but is a reasonable step in the right direction. Let’s hope Congress gets to it soon.
• Food advertising and labels: The long-dormant FDA and Federal Trade Commission are getting busy at last. In the wake of the Smart Choices fiasco, the FDA is working to make package labels less misleading and easier to understand. The agencies have proposed nutrition standards for products marketed to children. These voluntary standards fall far short of my preference – an outright ban on marketing junk foods to kids – but puts food companies on notice that their products are under scrutiny. The FDA is also working on designs for front-of-package labels. I’m hoping it chooses a “traffic-light” system that marks foods with a green (any time), yellow (sometimes) or red (hardly ever) dot. Expect plenty of opposition from the makers of red-dotted products.
• Meat: The meat industry has been under fire for raising food animals under inhumane conditions, using unnecessary hormones and antibiotics, mistreating immigrant labor, and polluting soil and water. Now it is also under fire for contributing to climate change. Recent films like “Food, Inc.” and “Fresh” and books such as Jonathan Safran Foer’s “Eating Animals” are encouraging people to become vegetarians or to eat less meat to promote the health of people and the planet. I’ll bet the meat industry pushes back hard on this one.
• Sustainable agriculture: The back-to-the land movement has loads of people buying local food, choosing foods produced under more sustainable conditions and growing their own food. The number of small farms in America increased last year for the first time in a century. Seed companies cannot keep up with the demand. It will be fun to follow what happens with this trend.
• Genetically modified (GM) foods: My book, “Safe Food,” comes out in a new edition this year, so I am paying especially close attention to debates about GM foods. The FDA’s 1994 decision to prohibit labeling of GM foods continues to haunt the food biotechnology industry. By now, nearly all American soybeans and sugar beets (95 percent) are GM, as is most corn (60 percent). But when the U.S. Department of Agriculture approved GM sugar beets in 2005, it neglected to perform the required environmental impact assessment. On that basis, environmental groups want to ban further planting of GM sugar beets. The dispute is now in the courts.
• Chemical contaminants: The FDA has yet to release its report on the safety of bisphenol A, the plastic chemical that acts as an endocrine disrupter. Shouldn’t it be banned? The bottling industry says no. Watch for fierce arguments over this one.
• Salt: Nutrition standards allow 480 mg sodium (the equivalent of more than 1 gram of salt) per serving. A half cup of canned soup provides that much. A whole cup gives you 4 grams and the whole can gives you 8 grams – much more than anyone needs. Nearly 80 percent of salt in American diets comes from processed and restaurant foods. Companies are under pressure to cut down on salt. Will they? Only if they have to.
• Dietary advice: The new edition of Dietary Guidelines for Americans, which the government publishes every five years, is due this year. What will it say? I can’t wait to find out.

Those are the issues I am tracking these days. My one crystal-ball prediction? We will be hearing a lot more about them this year.

Happy new year!

I am, as always, indebted to Bill Marler for his ongoing commentary – often with slide shows – on recalls of foods contaminated with E. coli O157:H7 and other nasty bugs.  He offers ongoing comments about the Christmas eve recall of 248,000 pounds of needle-tenderized steaks.

He points out that the recall now affects people in several states and that the meat was intended for several chain restaurants.   The contaminated meat, produced in Oklahoma, has sickened at least 19 people in 16 states.

Mechanically tenderized “non-intact” beef?  Uh oh.  The great thing about intact steak is that harmful contaminants are on the outside surface; the bacteria get killed by the high heat of searing the outside surface.  You don’t have to worry about the safety of intact steak because its insides are relatively sterile.  But if the steak is pre-treated to tenderize it, watch out!  Tenderizing can drive harmful bacteria right into the interior where they won’t get killed unless the steak is thoroughly cooked.

To explain the problem, Marler posts a slide show from Dave Boxrud.  Here is one of Boxrud’s illustrations:

Marler provides links to documents showing that the USDA has received plenty of recent warnings about the dangers of undercooked non-intact beef.  This is no surprise.  In my 2003 book, Safe Food (coming out in a new edition in 2010), I discuss the USDA’s “testing gap” with respect to nonintact beef.  In 1999, the USDA said that it wanted to extend its testing requirements for ground beef to mechanically tenderized beef that might be contaminated with E. coli O157:H7.

In Safe Food, I explain how the beef industry reacted with “shock, disbelief, and anger” to the USDA’s safety proposal.  One industry representative accused the USDA of taking “another step in this administration’s obfuscation of the impeachment activities.” Those activities, of course, referred to the scandal then involving President Clinton and the White House intern, Monica Lewinsky.

Then, the meat industry’s position was that pathogens were inherent in raw meat, cooking kills them, and testing would put the industry out of business. Ten years later, the industry position hasn’t budged. The Washington Post (December 30) quotes beef industry representatives arguing that mechanical tenderizing poses no particular health problems.

According to Food Chemical News (September 28), Congressional representative Rosa DeLauro (Dem-CT), who chairs the House appropriations agriculture subcommittee, has called on USDA to take immediate action to require labeling of meat that has been mechanically tenderized.

And USA Today (December 30) has produced another long investigative report on the safety of school meals, this one citing plenty of examples of companies that successfully produce or serve safe meat and of countries that do food safety better than we do.  In the meantime, the food safety bill is still stuck in Congress.  Let’s hope that it gets moving early in 2010.

Addendum: The New York Times (online December 30) also is interested in beef produced for the school lunch program.  Its reporters investigated safety problems with beef trimmings that had been injected with ammonia to kill bacteria.    Two things about the beef trimmings are especially interesting.  One person is quoted in the article referring to them as “pink slime.”  And they used to be used for pet foods until meat packers figured out that selling them to USDA for school lunches was more profitable.

As for the ammonia treatment: surely this is not the same stuff used to clean bathrooms?  Apparently so.  But using it is tricky.  You have to inject enough ammonia to kill bacteria but if you do the meat smells like an ammonia-treated bathroom.  If you don’t want the meat to smell, you can’t use as much.  But if you don’t use as much, you get Salmonella. This, alas, is another example of regulations not working.

Congress: pass the food safety bill and then start working on a single food safety agency!

Update January 7: The CDC has posted information on its investigation of this outbreak on its website.

A reader, Valerie Watkins, comments on my previous post about the long delay in settling the lawsuits over the pets harmed by the melamine scandals of 2007.  She writes:

The internet has several articles indicating the law firm that is handling the money helped themselves to the cash and there is no money remaining. Several reports indicate there are NO objections by anyone, it is just the law firms response to not allowing the claims to be paid out. After 3 years of waiting, I believe it. Pet owner’s will wait for nothing, the money appears to have been spent on those trusted with paying out the claims.

Oh dear.  The Internet is a wonderful invention but has one serious flaw: its content is unedited.  People can say whatever they like no matter how far from the truth.  I have learned not to trust anything I read on the Internet unless I know that its source is reliable.

My immediate reaction to Valerie’s comment: Could this possibly be true?

No, it most definitely cannot.

Take a look at the court documents.  Two appeals are still pending in the Third Circuit court. Until those appeals are settled, the money is in escrow and nobody – not even the lawyers – can touch it.  The documents clearly state that the lawyers are not to be paid until all appeals are resolved and the judgment is in effect.

The administrator of the settlement explains:

No payments may be made on eligible claims until all appeals are resolved. THE APPEALS HAVE BEEN FULLY BRIEFED AND WE NOW AWAIT THE DECISION OF THE APPELLATE COURT. It is uncertain how long these appeals will take to resolve, and the timing of resolving the appeals is not within the control of the parties or their counsel. It is not uncommon for appeals to take several months or even years to resolve.

For anyone with a pet harmed by eating tainted pet food, the long delay is painful.  It would be a help to have the settlement resolved.   But the delay is not caused by the lawyers who are representing aggrieved pet owners.  It is also in the lawyers’ best interest to settle the suit as quickly as possible.

When it comes to the Internet, don’t believe everything you read.  And check sources!  In case of the pet food class action suit, the documents are on the Internet and available to everyone who takes the trouble to see what they really say.