Diabetes and Your Diet: A Primer


Experts predict that one in three Americans could have type 2 diabetes by 2050.  Here is the latest science on how to eat to treat, and prevent, the disease.

Living with a chronic medical condition is never easy, but for people with diabetes, there was always the extra challenge of carbohydrate counting, a limited diet, and exercise drudgery.  No longer.  Thanks to recent findings about how the body processes nutrients, experts are redefining what it takes to manage and, in the early prediabetic stages, even reverse the condition.  Add to this new science the increasing demand among all Americans for tasty-yet-healthy food (like the gargantuan salad bar at Whole Foods) and you’ll see that eating with diabetes and living healthfully have become one and the same.


What is diabetes?

To appreciate the shift in how experts treat diabetes, it helps to understand what causes this chronic condition and the vast number of people it affects.  Twenty-nine million Americans (about 9% of the population) were living with diabetes in 2012.  Of those patients, 1.7 million were new cases, and the growth rate is expected to rise every year.

Five percent of patients have type 1 diabetes, which is a disease of autoimmunity.  With this disease type, which typically first appears in children and young adults, the pancreas inherently produces almost no insulin, the hormone that ferries glucose into the blood to cells throughout the body, where it is converted to energy.  Glucose is the molecule created after your digestive system breaks food down.

Most diabetes sufferers are type 2, which is a lifestyle disease.  Men and women are equally affected, but it’s more common among those over the age of 50 and those of Hispanic, African, Native American and Asian descent.  With type 2, the body produces insulin, but not enough to accommodate glucose levels in the blood; or the insulin can’t function properly.  A third type, gestational diabetes, is similar but occurs temporarily, in pregnant women.

When glucose is left in the bloodstream and its concentration rises, the body urinates some of the extra glucose, pulling water from cells throughout the body.  This is why symptoms in undiagnosed diabetes include frequent urination, thirst and fatigue.  If left untreated, the glucose can make it hard for the organs, especially the eyes, kidneys, nerves and heart, to do their jobs.

It’s unclear why diabetes develops.  Researchers now know that excess body fat produces compounds that lower sensitivity to insulin.  This may explain why about 80% of people with type 2 diabetes are overweight.  But experts aren’t sure why it occurs in the 20% of patients who are not heavy, nor why most overweight people never develop diabetes.  This suggests that other environmental factors (such as physical activity) and genetics come into play.  Insulin injections and other glucose-reducing medications are often used to treat the disease.  But diet and exercise remain crucial.   If you’re not careful, you can out-eat any medication.


The Diabetes Diet

As recently as five years ago, dietary guidelines still emphasized specific limits on carbohydrates and dietary fat.  At the time, less appreciation was placed on the hugely varying effects that different carbohydrates and different fats have on the body, and the protocol for treating diabetes trended toward a more one-size-fits-all program.  But the most recent guidelines championed a healthful eating pattern above all.  A goal of healthcare providers should be to maintain the pleasure of eating by providing positive messages about food choices.  This leaves lots of room for flavor, not only from the long recommended categories of leafy and cruciferous vegetables and lean proteins, but also in the two major food categories of most concern to those with diabetes: carbohydrates and fat.  Carbohydrates still need to be kept in check, because they break down more directly into glucose than protein and fats.  But now actual counts are ‘individual’.  The quantities recommended for you may depend on a host of factors, including your activity level, weight, and extent of insulin resistance.  One type of carbohydrate, namely whole or ancient grains, is not only tolerated but embraced.  High in fiber, whole grains won’t send a rush of glucose into the bloodstream the way processed carbohydrates (such as white bread, white pasta, and sugar) do.    They can not only improve insulin sensitivity, but also lower the glucose spike after a meal.   In fact, the whole or ancient grains contain the type of fiber most closely associated with reduced risk of type 2 diabetes.  Some examples of ancient grains include quinoa, amaranth, barley, polenta, bulgar, spelt, buckwheat, millet, freekah and farro.

Fats, of course, are high-calorie (9 calories per gram), which could lead to weight gain: a problem because excess pounds worsen insulin resistance.  So, like everyone else, people with diabetes should eat fats judiciously.  Saturated and trans-fats exacerbate insulin resistance by interrupting the signals sent between the insulin and the cells that pick it up; watch those portions even more carefully (completely eliminate trans-fats!).  To add richness to your meals (and score more health points), focus on unsaturated fats, like the omega-3 fatty acids in salmon, sardines and halibut as well as some nuts (walnuts).  They’re natural anti-inflammatories (meaning they help temper an overactive immune system), which is a big benefit to diabetes sufferers given that recent research suggests that diabetes is associated with inflammation.  Another good choice: the monounsaturated fats in avocados, olive oil, nuts, and seeds, which have been found to lower blood glucose levels when combined with whole/ancient grains.


The Sugar Shift

Sweets have always been a rare indulgence for people with diabetes, and they continue to be.  But with a better understanding of how natural and artificial sweeteners affect the body and the brain, some doctors are moving toward more specific advice.  Granulated sugar and high fructose-corn syrup (HFCS): Both of these consist of glucose and fructose molecules.  However, HFCS, found primarily in soda and sweet processed foods, contains a higher ratio of fructose.  When foods containing this higher ratio of fructose are consumed, the prevalence of diabetes goes up 10 times more than it would have if these foods had not been consumed.  This suggests that it’s not the calories from these sweeteners that may exacerbate diabetes but the content of them (specifically the processed fructose, experts say), which seems to impair the body’s ability to regulate blood insulin levels.  Dietitians say that the best way to temper a sweet craving, whether or not you have diabetes, is a small serving of fruit.  While fruit does contain naturally-occurring fructose, it also contains good-for-you fiber.  Limit sweet treats with granulated sugar to special occasions (and about 100 calories’ worth), and completely eliminate HFCS from your diet.  Replace carbohydrates with vegetables, protein and healthy fat foods in your meals throughout the rest of your day.  Sugar Alcohols: Sorbitol, mannitol, maltitol and xylitol raise blood sugar, but not as quickly as sugar does.  The problem with the sugar alcohols is that they cause diarrhea/watery stool in most people, and so are not well-tolerated.  Artificial sweeteners or sugar substitutes: NutraSweet and Splenda don’t raise blood sugar levels at all.  They may, however, alter the bacteria in the gut, which in turn may increase blood glucose levels.  If products with sugar substitutes are used, it is recommended that they are limited to one serving per day.  Try substituting one small serving of fruit or the occasional bite-sized treat made with real sugar, or a carbonated beverage (8 oz) made with real sugar and not HFCS.


The Exercise Factor

Doctors have known for decades that muscle contractions stimulate glucose uptake from the blood.  To that end, they’ve advised diabetic patients to take brisk walks for half an hour a day, every day.  But now experts suspect that timing may be as important as intensity and duration, at least from a glucose-control standpoint.    A 15-minute walk 30 minutes after each meal (for a total of three meals per day) controls blood sugar better than a long, 45-minute morning walk does.  Blood sugar rises after eating, so you reap more gains from the same effort.

For more information, see your physician, registered dietitian, or certified diabetes educator.

Courtney Rubin