Sugar is sweet. We all know that. Sugar performs many other roles in food that make it a valuable ingredient in food. We call these roles functional properties. Sugar is important in home-cooked meals. Sugar is also important in manufactured foods. Absence of sugar in a recipe or formulation may result in inferior quality of the food. Formulations are scientific versions of a recipe. Food factories produce formulated foods in mass quantities.
Sugar may also present a danger to those who consume it. A general consensus concludes that we eat too much sugar. Sugar adds calories and contributes to weight gain for those of us who eat too much. Some authorities suggest that added sugars cause diabetes, heart disease, and premature death. Are these concerns valid or overblown?
The molecular form of the sugar matters. Structure affects the functional properties of the sugar. Structure may also affect the potential danger of the molecule. We also divide sugars into two types: natural and added. Can our bodies really distinguish between natural and added forms? Are we more likely to overconsume added sugars than natural sugars? Do foods prepared with sugar as a culinary ingredient at home pose a danger? Is that danger less than sugar added at a processing plant? What do the new dietary guidelines say about added sugar? I explore these questions and related propositions below.
Functional properties of sugar. In food prepared at home sugar is more than a sweetener. Reducing sugars contribute to browning of baked goods and glazes. Browning reactions contribute new and novel flavors as well as desirable colors. Sugars also affect the texture of baked goods like cookies. Precise measurements of sugars are important to avoid excess browning. Brown sugar is an important ingredient in maintaining shape of foods like baked beans during cooking. Sugar lowers the temperature of homemade ice cream giving it a creamier texture. Also, sugars form syrups which thicken foods and beverages. A critical function of sugar in processed food is that it binds water preventing microbial growth. Microbes cause food to spoil or to become unsafe.
Health consequences of consuming too much sugar. Sugar contributes calories in a very appealing form. Calories contribute to weight gain. We live in a nation of overweight and obese people. But, do sugars pose a risk greater than the calories they contribute? Ultra-processed foods may cause nutrition-related diseases and premature death. A recent study suggests that added sugars are to blame (1). An alternate theory indicates that browning reactions are responsible leading to production of toxic compounds. These are changes that occur in home baking and cooking of meats as well as browning in processed foods. A third perspective suggests that these relationships are due to Random Error. If the problem with sugar is the calories, we need to moderate the amount we consume. If the problem is more serious, then we need to minimize our sugar consumption.
The many forms of sugar. The FDA has differing labeling regulations for added and natural forms of sugar in processed foods. Honey, maple syrup, and table sugar pose a problem to regulators. At first the FDA labeled these products when sold as added sugar. Such labeling proved confusing.
How can a bag of table sugar be a package of 100% added sugar? FDA is working with manufacturers of single-ingredient sugar products. An explanation on the label for consumers will explain this apparent contradiction. To a food scientist it makes no sense to call honey etc. an added sugar when present in a processed food but not in a homemade one. Natural sugars include those from fruits, milk and other whole foods.
There are at least 49 ingredients added to foods that are sugar as highlighted in What the Fork are You Eating? Critics call out the food industry for hiding sugar in products. It lists many sugar ingredients on a label making it appear like there is less sugar present. Writers of books and published recipes use the same tricks. They use many forms in the same recipe. They also substitute ingredients like brown rice syrup for sugar. The best way to determine the amount of sugar in a packaged food is to look at the Nutrition Facts on the label. This panel provides the amount of total and added sugars present in a single serving. Checking the serving size is important to keep from consuming too much sugar. For example, I once ate an entire packaged muffin. It was very good for so little sugar. I doublechecked the label only to discover that the serving size was half the muffin! Note that the amount of total or added sugar is not available for a fruit, vegetable, or home-baked food.
There are also many molecular forms of sugar. Table sugar is pure sucrose, possibly the most pure and refined ingredient present in processed and homemade foods. Sucrose is broken down into equal parts of glucose and fructose in the body. Glucose is blood sugar. Fructose is found in high fructose corn syrup, honey and agave syrup. Maltose is composed of two molecules of glucose. Lactose is milk sugar and broken down to glucose and galactose.
Effects of sugar forms on functionality. Shirley Corriher describes the different functional properties of selected sugars in KitchenWise. The most widely used sugar in the kitchen is sucrose, found in table sugar. Different types of sugar vary in the level of sweetness they deliver. Of the main sugars present in food, fructose is the sweetest. Sucrose is intermediate in sweetness. Glucose and lactose are not as sweet as fructose and sucrose. Sucrose is not a reducing sugar and does not lead to browning. Fructose and glucose are reducing sugars and thus contribute to browning. Too much reducing sugar reduces the visual quality of the food. Sugar syrups can serve as thickeners. Granulated sugars contribute to the texture of baked goods. In home baking and processing the importance of sugar extends far beyond its level of sweetness.
Effects of sugar forms on health. During digestion the body can’t distinguish the difference between natural and added sugars. Digestion breaks down big molecules into small molecules. These small molecules gain entry into the bloodstream through intestinal walls. Then they are transported to cells where they again become parts of large molecules.
Why do we make such a big deal to distinguish natural from added sugars? In part, natural sugars are associated with vitamins, minerals, and fiber. Added sugars, not so much. It is also harder to binge on oranges and apples than glazed donuts or cupcakes. The distinction breaks down when it comes to natural sugars in honey and maple syrup. Yes, they do contain minerals. To ingest enough minerals from honey or maple syrup, we would end up consuming way too much sugar. As far as sugar from fruit, bananas and mangoes are high in sugar. Consume them in moderation. Grapes have high levels of glucose and thus represent a danger to diabetics. Dates and raisins have natural sugars, but they are also easy to overconsume.
Brown rice syrup, a popular substitute in alternative recipes, is almost all maltose and high in arsenic. Maltose contains two glucose molecules, posing a danger to diabetics. The most controversial form of added sugar is high fructose corn syrup. Some studies indicate that it causes non-alcoholic, fatty liver disease (2). Others suggest that is no more harmful than table sugar or honey (3).
The new dietary guidelines failed to lower the recommended levels of sugar from 10% to 6% of total calories. Their scientific advisory board advised the reduction. The guidelines did not incorporate that recommendation. Will a reduction from 50g to 30g of added sugar each day in the typical American diet make that much of a difference in our health? I doubt it. 50g is a small amount. 30g is very hard for a typical American to achieve. The New York Times criticized the guidelines for failing to lower consumption of added sugars. That same day it published a recipe for peanut butter-miso cookies. The recipe calls for 3 types of sugar totaling 425g. The recipe makes 16 cookies or 26.5g added sugar per cookie. That leaves the typical American a total of 3.5g of added sugar for the rest of the day after eating one cookie. Two cookies exceed 50g. Are homemade cookies fresh out of the oven less enticing than cookies out of the oven? No way!
A reduction from 50g of added sugar to 30g each day is not realistic. American health would improve if consumers of more than 100g of sugar a day lowered their consumption to 50g. If we are serious about consuming 30g of added sugar or less a day, we should avoid all processed and homemade sweets.
Critical questions answered
Can our bodies really distinguish between natural and added forms?
No, digestion is all about breaking down and rebuilding ingested molecules.
Are we more likely to overconsume added sugars than natural sugars?
It depends. Yes, if the natural sugars are located in whole fruits. No, if the natural sugars are from honey or maple syrup. Bananas, mangoes, grapes, dates, and raisins could also pose problems.
Do foods prepared with sugar as a culinary ingredient at home pose a danger?
Yes, if added sugar poses a danger to human health.
Is that danger less than sugar added at a manufacturing plant?
No. Sugars added at home are just as dangerous as those added at a processing plant. The idea that sugars are much higher in processed foods than homemade ones is false.
What do the new dietary guidelines say about added sugar?
The new guidelines ignore the recommendations of the advisory panel. They keep the daily level of added sugar at 10% of calories.
Next week: The Twinkies caper: Separating processes from ingredients
(1) Bonaccio, M., A. Di Castelnuovo, S. Costanzo, A DeCurtis, M. Persichillo, F. Sofi, C. Cerletti, M.B. Donati, G. de Gaetano and L. Iacoiello, 2020. Ultra-processed food consumption is associated with increased risk of all-cause and cardiovascular mortality in the Moli-sani study. American Journal of Clinical Nutrition https://doi.org/10.1093/ajcn/nqaa299
(2) George, E.S., A. Forsyth, C. Istiopoulos, A.J. Nicolai, M. Ryan, S. Sood, S.K. Roberts, and A.C. Tierney, 2018. Practical dietary recommendations for the prevention and management of nonalcoholic fatty liver disease in adults. Advances in Nutrition 9:30-40.
(3) Prinz, P. 2019. The role of dietary sugars in health: molecular composition or just calories? European Journal of Clinical Nutrition 73:1216-1223.