“Eating well is an art. It doesn’t require fancy cooking, but it does require practice and concentration. Your body is not just yours. It is a gift and a responsibility. To keep healthy, we need to know how to eat.” - Thich Nat Hahn
Sugar is our enemy. It is a toxin, acting like poison when digested by the body. Sugar influences our feelings of satiety, metabolic rate, brain chemistry, and hormones in ways that are different from other nutrients. Overconsumption of sugar leads to fatty liver disease and heart disease, and may be a primary cause of heart disease. Ready to throw away your cookies? Well, don’t. Although these claims were made by researchers and scientists, none of these claims have, over the past two decades, been substantiated. In fact, as more research is done related to the effects of sugar, the results are even more inconclusive, providing less evidence to substantiate these claims.
Sugar is the latest victim in our country’s long history of demonizing food. The simple graham cracker that we know today started in the 1830’s as an alternative to commercially prepared white bread. Sylvester Graham, an evangelical minister, believed that a diet high in meat, fat, and white bread caused brain inflammation, a “lazy gut”, and increased sexual drives that destroyed the sanctity of the family unit. He developed a whole wheat flour that was quite healthy. He marketed and sold the flour to women who would then make the bread at home, which he believed as the first step in restoring balance and chastity on the home front.
Since 1830, several foods have served their sentence in the nutritional slammer. In the 1980’s, the victim was fat. Heart disease was occurring at epidemic levels in the U.S. and Europe in the years after World War II. Ancel Keys, a physiologist who studied the influence of diet on health, conducted research in the 50’s and 60’s on the nutritional causes of heart disease. His studies pointed to saturated and trans fats as being the primary drivers of cardiovascular disease. His work had some unintended consequences. Although his research focused on unhealthy fats, it tended to underplay the benefits of unsaturated fats, which was misinterpreted as an indication that all fat was unhealthy. Nuts, avocados, and healthy cooking oils, important sources of nutrients, were demonized. This led to the disastrous “low fat” diet craze in which fat was replaced by sugar. Keys vehemently argued against it, stating that healthy unsaturated fats and protein rich complex carbohydrates such as beans should replace saturated fats. But enthusiasts ignored his cautionary statements, supporting the idea that the fat content of a food was more important than calories. The war against fat ushered in a generation of “low-fat” processed foods that made food manufacturers very wealthy (who can forget Snackwells?) but did nothing to shift the rates of heart disease and may have even created a spike in the rates of obesity and metabolic disorders.
There is a growing chorus of nutritional scientists who believe we are traveling down the same road with our current attitudes about sugar. Proselytizing about the evils of sugar is an oversimplification and misunderstanding of what we know about sugar’s role in health and makes the same mistake as demonizing fat. Our diets consist of foods, not nutrients. We don’t eat lumps of saturated fat, nor do we eat vast amounts of pure fructose. Nutritional wisdom gets muddled whenever we try to isolate specific nutrients as being problematic rather than taking a holistic view that focuses on eating small amounts of nutritious foods.
When we say that sugar is toxic, what type of sugar are we referring to? Talk of sugar brings up thoughts of cookies, soda, and candy, but it is a label that describes a wide range of foods. Carbohydrates, which have always been an important source of energy throughout the history of our species, come in three forms: sugar, starch, and fiber. Regardless of their size or type, they are made up of carbon, hydrogen, and oxygen atoms. They range from the very small, such as the two monosaccharides of glucose and fructose that are stuck together to form table sugar, to the long chains of simple sugars that make up starchy foods, such as tubers.
Fiber, however, is different. It is a type of carbohydrate that we can’t digest completely. Coming from plant sources, it is made up of tough, stringy molecules that give plants their strength and structure. Fiber from these complex carbohydrates goes to the large intestine where it coats the intestinal walls, providing a type of lattice that slows the absorption of sugars and other nutrients into the bloodstream. Importantly, fiber feeds our microbiome. As the microbes feed on the fiber, they produce vitamins and nutrients that help our digestion, support our immunity, and keep several body systems running properly.
Humans crave carbohydrates, and for good reason—they power our body with quick, easily accessible energy. Unlike fat or protein, a sugar molecule is broken down quickly and is then absorbed into the bloodstream to be used as fuel or stored for later use. Blood sugar that doesn’t get burned immediately gets repackaged in the body as glycogen. Since glycogen is a bulky and dense molecule that is heavy with water, our bodies have strict limits on how much of it can be stored. We store glycogen in the muscles and liver; athletes and very fit individuals tend to have more of these storage units in the muscle than people who are sedentary.
When the body’s energy needs are met and our glycogen stores are at capacity, excess sugar in the bloodstream is converted into fat. Although it takes more energy for the body to release energy from a fat molecule than it does a molecule of carbohydrate, converting excess glycogen into fat is a much more efficient way to store extra energy. And fat cells are a vast warehouse; whereas our capacity to store glycogen is limited, we all know that the possibilities for fat storage in the human body are endless.
For decades, proponents of low-carb diets have complained that the scientific community has turned a blind eye to the role carbohydrates play in obesity. They argue that carbohydrate-rich diets overload our glycogen storage capacity which then forces the body to store more of these calories as fat. They believe that a flood of carbohydrates into the bloodstream causes the body to overreact and put more energy into storage, leading to a drop in available fuel in the bloodstream. The body senses that it is low in energy, which triggers a hunger response and drives us to eat more. We eat more carbohydrates, which repeats the cycle. As fat levels rise, so does inflammation, setting us up for heart disease, high cholesterol, migraines, arthritis pain, and brain fog. Low-carb proponents believe we don’t get fat by overeating; obesity is a result of eating too many carbs that are converted into fat which then makes us overeat.
Like so many health claims that are fodder for the latest diet craze, the argument for a low-carb diet is attractive and, importantly, it sounds true, which in research circles is referred to as “truthiness”. It sets forth an elegant hypothesis, presents certain facts that are supported by research, but then takes a leap by making unsubstantiated or oversimplified conclusions. This is the stuff of best sellers, podcasts, and guest appearances on the morning news shows, but the biggest problem with the low carb argument is that it is simply not true. Over the years many studies have tested this hypothesis and none—even those with strict experimental designs that follow large populations—have shown that calories from carbohydrates have an enhanced capacity to make you fat. Most studies show that it is total calories that make the difference, not where they come from.
So why do people feel so much better when they “cut carbs” and “eliminate sugar”? Foods that are high in protein promote satiety faster than pure carbohydrates and take longer to digest, so you are likely to eat smaller portions and feel more satisfied with a low-carb meal than a big bowl of pasta with bread. Also, many of the “carbs” that are eliminated from a low-carb diet are of the packaged, junk variety. With an emphasis on vegetables and lean protein, highly processed breads, snacks, and desserts are traded for foods that emphasize the heart healthy foods Ancel Keys advocated: nuts, avocados, beans, and green vegetables.
Based on the current research, we must still say that a calorie is a calorie. We should not make the same mistake as we did during the fat-free craze of believing that one nutrient is more fattening or deadlier than another. What we eat clearly matters. Carbohydrates, whether they are eaten in the form of sugar, starch, or fiber, are not poisonous. They can, however, make us sick when we forget their primary purpose—they give us energy. Eating too many carbohydrates than we need for our current level of activity will result in an ever-widening storage area of fat. And there is lots of research showing the evils of excess fat; it creates inflammation, makes us more susceptible to cancers, fuels arthritis flare-ups, and leads to a host of metabolic diseases. Fred Brouns, a professor of Health Food at Masstricht University in the Netherlands says it best: “To say that sugar is toxic is a total misconception of the nature of the molecule. If you have too much oxygen, it is toxic. That doesn’t mean we say oxygen is toxic.”
Eliminating a food group, especially one as important as carbohydrates, is a dangerous nutritional practice. Humans have relied on sugars and starches for over 65 million years; our saliva contains more amylase, the protein that breaks down starch, than any of our primate cousins. Demonizing sugar, especially fructose, cuts us off from the important vitamins and minerals that fruits, root vegetables, and tubers offer. Caution should be taken that we do not confuse the sugar in soda, candy, and white bread with the sugar found in fruits and whole grains.
We like to demonize food because it creates a tidy narrative that makes us more likely to follow a diet, especially when it involves being disciplined and avoiding our favorite foods. But nutrition is far from simple: a theory that provides a neatly packaged argument for and against a nutrient is probably only partly true. It is best, however, to follow your gut—literally—when it comes to eating. If you feel better eliminating foods that are high in natural sugar and starch, then follow that nutritional path. Arguing about which diet is best—Keto, Paleo, Atkins, Mediterranean—is only relevant to you, not others. What matters most is the plan that feels best in your body, is easy for you to follow, and provides the greatest health benefits in the long term. Let’s drop the evil narrative, stop demonizing food, and simply start to enjoy eating again. If you like a simple narrative, then I suggest you follow the three rules of eating by Michael Pollen: “Eat food. Not too much. Mostly plants.”