COMMENTARY: A holiday-season dose of toxicology

For nutrition-conscious Americans, the holidays are a challenge. The war between the low-fat and the high-fat diets is reaching a fever pitch, and the coming announcement in the new dietary guidelines recommending more butter and lard will only confuse the issue.

Rather than pick a side in the war between “experts,” a better strategy may be found in the science of poisons: toxicology.

The founding principle of toxicology can be summarized this way: “Dose makes the poison.”

In other words, almost anything is a poison if we’re exposed to too much, too fast. Water is toxic. If you consume a gallon in an hour or two, it can lead to coma or death. On the other hand, it takes a microscopic amount of botulinum toxin to kill you.

We can apply a similar idea not just to chemicals and radiation, but to eating. While what we usually do between Thanksgiving and Christmas — overcooking, gobbling everything in sight and stuffing ourselves until we are nearly sick — is tradition, most of the time we should go back to these words from the Agriculture Department’s Dietary Guidelines for Americans in 1980: To improve eating habits, “Eat slowly, prepare small portions” and “avoid ‘seconds.’”

All but forgotten, we are bombarded with a war of government agencies and everyone else pushing their preferred diets, claiming they are right for everyone. There are two problems here. First, there’s a staggering amount of bad data and weak nutrition science out there. Second, because we are all different, we may need different diets.

Most of the nutrition research data comes from asking people to write down or recall what they have eaten. As scientist Edward Archer has shown, this data is often “incompatible with life” — meaning people don’t report eating enough to stay alive. Also, nutrition science can show only associations. It’s extremely difficult to show that any specific diet will actually help us avoid chronic diseases caused by poor nutrition.

The original recommendation to eat less fat, later narrowed down to saturated and trans fats, was promoted in the 1950s by physiologist Ancel Keys. Currently, two-thirds of Americans exceed the 10 percent saturated fat per day, although holiday foods cause most of us to exceed the daily recommendations — sweet potato casserole (83 percent) and mashed potatoes and gravy (36 percent).

Critics such as Nina Teicholz in “The Big Fat Surprise” argued that Key’s recommendations were based on weak correlations and were adopted over time because of groupthink. Her prescription is to eat more saturated fat, a position now adopted by the Trump administration.

The proponents of avoiding a high-saturated-fat diet, in turn, charge that the opposing claims rely on observational studies that are too small. In other words, each side argues that its opponents rely on weak scientific evidence.

Both sides are right, and there is no end to this war in sight.

The other issue with “everybody needs to eat the same diet” advice is that we are all different. Modern science is now turning to precision nutrition and individualized health recommendations. Here’s where the real promise lies.

We know that individual genetics, microbiomes, environment, health conditions, medicines and more cause us to metabolize foods differently. This makes much of the war between diets misguided. New tools for monitoring what we eat, biomarkers for internal responses to foods, and artificial intelligence are leading us away from arguments about universal diets.

Meanwhile, one thing we should be able to agree on is that we eat too much. On average, Americans have increased caloric intake by 25 percent and obesity rates have increased by 25 percent (15 percent to 40 percent).

Maybe it’s because foods taste better now, such as hyperpalatable, ultra-processed foods. There have always been good-tasting foods, and we need to exercise more agency over our own choices. We tend to eat fast, unlike Europeans who linger at the table, allowing the 20 minutes it takes to feel full.

Even if you break a few rules this holiday season, think about dose and response. Slow down and eat less. Instead of massive servings, exercise good eating habits, get up and go for a walk and feel great the next day.

Richard A. Williams is a former director for social sciences at the Center for Food Safety and Applied Nutrition in the Food and Drug Administration. He wrote this for InsideSources.com.