“Adopt the pace of nature. Her secret is patience.” - Ralph Waldo Emerson
Fat-free foods are healthier than high-fat foods. Fresh produce is more nutritious than canned. People with Type 2 diabetes should avoid eating fruit. Plant milk is better for you than dairy milk. Weight loss is a simple balance of calories in, calories out. These statements have one thing in common: none of them are true, but they persist in our culture as fact, part of a cluster of unproven nutritional claims that persist regardless of evidence to the contrary. Most nutritionists wish these myths would go away as they do more harm to our health than good.
Nutrition science is not easy; it is hard to study food in a way that accurately reflects how we eat. Understanding how different ingredients in a food promote or impede our health is complicated by a wide range of interwoven variables, including where a food is produced, how it is prepared, how much of it we eat, its role in our overall diet, genetic factors, the health of our digestive system, and a person’s lifestyle. The only method scientists have to study food is to break it down and examine its nutrients, a tool which most nutrition scientists agree is ill suited for such a complex task. Marion Nestle, a New York University nutritionist summarizes this dilemma perfectly:
“The problem with nutrient-by-nutrient science is that it takes the nutrient out of the context of the food, the food out of context with the diet, and the diet out of context of the lifestyle.”
Even the most basic of foods—a carrot, an apple, a glass of milk--is an incredibly complicated array of chemical compounds that exist in a dynamic relationship with each other. Reducing food to its nutrients paints a simplistic picture that can be confusing and misleading. It encourages the misguided belief that eating a food with a given nutrient results in a specific physiological response. Yet rarely is this true in real life. We all know the person who eats a poor diet and never gains weight, a friend who consumes plenty of Vitamin C and still gets colds, or the conscientious dieter who follows a strict vegan diet but cannot get his LDL cholesterol to budge. There is nothing simple about the human eater, so focusing exclusively on a food’s nutrients leads to confusion and the perpetuation of pernicious food myths.
Not only is the composition of a food complicated, it is only one part of a much larger whole that comprises what we refer to as our diet, which includes what we eat, when we eat, and how we combine foods. All of these factors affect how foods are metabolized. Eating an apple by itself can send a diabetic’s blood glucose levels soaring, but doing so with cheese and almonds can slow down the absorption of the apple’s natural sugars. Having a cup of coffee with your eggs and steak reduces the amount of iron you will absorb from the meat. Drizzle olive oil on your tomato and you will absorb more of its lycopene. Nutrition science can uncover the nutrients in a food, but it does not explain how foods interact, why one person can easily digest a food while another cannot, or how one nutrient can break down compounds in another food or stimulate the enzyme production needed to detoxify a substance in something else.
Putting a spotlight on only one or two of a food’s ingredients narrows our understanding of a food’s relative risks or benefits. Studies published in the late 1940’s found correlations between diets high in fat and elevated rates of heart disease. For the next 40 plus years, the medical community advised the public to reduce fat in their diet as a means of lowering the risk of cardiovascular disease, even though the evidence that a low-fat diet prevented heart disease, reduced obesity, or supported weight loss was inconclusive. The vilification of fat led people to replace calories from fat with refined carbohydrates or added sugars—remember substituting applesauce for butter in baked goods? People’s consumption of refined carbohydrates soared in the 1980’s and 1990’s while obesity rates skyrocketed. The only people who benefited were the manufacturers of low-fat baked goods, chips, crackers, cheese, and dairy products, as these products used cheap ingredients and offered good profit margins. We now know that it is only saturated and trans fats that increase your risk of heart disease, while the naturally occurring fats found in olive oil, walnuts, fish, and flaxseeds reduce your risk.
When we are sick or in pain with a condition that is pernicious or hard to diagnose, we naturally crave simple, straightforward explanations for our misfortune. Blaming a nutrient in a food, whether it be high fructose corn syrup, gluten, or trans fats, is attractive because it solves a mystery while offering a solution that is within our control. It is comforting to believe we need only eliminate a “bad” ingredient from our diet to feel better. Of course, there are people who struggle for years with poor health that do finally get relief by eliminating a single nutrient, such as those with celiac disease who become much healthier when they eliminate gluten. But most chronic conditions are not so straightforward; other conditions such as irritable bowel syndrome, non -celiac gluten hypersensitivity and what is referred to as a “leaky gut” are harder to diagnose and to treat, with many different nutrients implicated along with lifestyle factors such as stress and one’s sleep habits.
The form in which a food is eaten is just as important as the nutrients it contains. Drinking fruit juice can spike blood glucose levels, whereas eating the fruit can yield a slower reaction due to the fiber content in the fruit’s skin. Almonds are a healthy snack that contain plenty of fiber, protein, and vitamins but, when processed into milk, offer much less protein than cow’s milk and may come with added sodium and sugars to help extend shelf life. Your breakfast cereal may list “bran” or “whole wheat” as the first ingredient, but that grain has gone through an extensive industrial process that completely reconfigures the grain into something quite different from its original form.
Food manufacturers reassure us that what matters most is the nutritional value of a food, not how it is delivered. Such a claim is underscored by our use of nutritional labels. With its list of ingredients, percentages, and calories per serving, these labels give the false impression that everyone who eats the same food, in the same amount, will ingest the same level of nutrients. These assumptions are contrary to what we are learning about human digestion. The human digestive system is incredibly complex and, even now, is not fully understood. It is lined with as many neurons as the spinal column, has sensors for taste as well as neurotransmitters—95% of the body’s serotonin is produced in the intestine—as well as regulates an intricate hormonal system, all while hosting a lively colony of microbial residents, such as Firmicutes and Bacteroides. In short, your intestines are an entire ecological system that is highly personalized, influenced by your genetics, lifestyle, and environment, and will determine how you digest certain nutrients and how those nutrients impact your health. Your gut is a very busy place, one in which the way in which a nutrient is delivered matters a great deal.
The length of the small intestine is roughly 9 to 16 feet long, while the large intestines are shorter, about 5 feet in length. Mother nature is incredibly pragmatic, so there is a reason our intestines are so long: human digestion is meant to be a slow and deliberate affair. That it is aided by the parasympathetic nervous system supports the importance of its slower pace. Digestion is a long series of important chemical reactions, an elegant yet efficient process that is more complicated than what we typically think of as a simple manufacturing of fuel. The mouth is the first step in digestion, where our teeth, chewing, and saliva mash down our food so it can travel safely through the esophagus and into the stomach, where it is ground down and exposed to acids that break it apart. The food then enters the small intestines, where it travels through an elaborate process of transformation and nutrient absorption. The substances that remain after traveling through the small intestine—fiber and other leftovers—then move to the lower intestines which start different physiological processes. In the large intestine, further digestion signals sensations of satiety and where various leftover undigested particles, such as fiber and plant cellulose, feed microbial colonies. It is here where we absorb water and balance our electrolytes. Each part of a food’s long journey through our digestive system is specific, with each playing an important role in our overall health.
Humans have been processing food for thousands of years through methods such as cooking, grinding, and milling. Some nutrition scientists argue that it is our current method of industrial processing that has a more pronounced effect on our health than those used by our ancestors. Most of the grains that are used in breakfast cereals, corn chips, and crackers are milled with industrial techniques, which use a variety of high-pressure techniques that dramatically alter the chemical structure of grains, breaking down their long chains of glucose and destroying the original starch molecule. By changing the structure of the carbohydrate, these industrial processing methods create shorter starch molecules that are digested much more rapidly, dramatically altering the way it moves through the digestive tract and into our bloodstream.
Our long and winding intestinal tracts are an evolutionary adaptation that allow us to extract nutrients from food gradually. Grains and other foods that have been chemically altered through industrial processes no longer need time to be digested; they move through our systems quite quickly, releasing glucose and nutrients in the very first part of the small intestine, circumventing the need for a food to continue its journey through the digestive tract. Processed foods may have the same nutrients as whole foods but their impact is quite different. They short-circuit our innate biology, speeding up the absorption of nutrients ahead of schedule, flooding our systems with glucose and insulin, failing to turn off our hunger signals, and by-passing our microbiome.
Food is more than just nutrients, eating is more than just refueling, and digestion is more than just processing. Over the millennia, we developed a delicate system that requires us to expend energy to find, prepare, and eat our food, while requiring rest and patience for the slow and deliberate process of digestion. Any food that attempts to bypass this process is sure to create chaos in our bodies. More importantly, any food that is incompatible with the intricate process of digestion will not, in the long term, nourish us, no matter how many nutrients it may contain.
The next time you sit down for a meal (and be sure that for at least one meal of the day you are sitting down), take time to look at the food in front of you. Use as many of your senses as possible—smell the food, notice the colors, look at how it is arranged on your plate. Take a long exhale and allow yourself to relax. Then take your time to enjoy your food, to really taste it, to notice the subtle changes as your body starts to digest—a process that works best when we are calm and centered. When our food and our eating is compatible with our biology, nutrition becomes more than an ingredient on a label. It is transformed into a process that can restore us, helping us generate the energy to start the cycle over again.
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