QUESTION: Could you tell people like me with Type 2 diabetes what you recommend we eat and drink? Everyone knows we should minimize sugar, but what else does the science show helps?
ANSWER: The most common tenet for an eating plan with diabetes -- minimizing sugar and refined carbohydrates -- still holds. But that doesn't mean you should be eating a lot of sugar substitutes.
In recent years, the use of sugar substitutes in ultra-processed foods has risen. At the same time, newer data has emerged challenging the assumption that these sweeteners are entirely "healthy."
This category includes natural non-sugar sweeteners, such as steviol glycosides, and artificial sweeteners such as aspartame and sucralose. For people with diabetes, these sweeteners have been long advised in place of sucrose, or table sugar, because they don't create elevations in blood sugar that can increase the risk of damage to the eyes, kidneys, blood vessels and heart.
But mounting evidence suggests that long-term use of diet beverages and non-sugar sweeteners may worsen our ability to regulate glucose -- among other concerns. In fact, in 2023, the World Health Organization recommended against non-sugar sweeteners for weight loss, citing an increased risk of Type 2 diabetes but also heart disease and early death.
My advice: Focusing on whole foods, rather than ultra-processed foods, is the backbone of a healthy diet -- whether you have Type 2 diabetes or not. So while occasional diet drinks as a substitute for regular soda is probably fine, most of the time, water remains the ideal option for people with Type 2 diabetes and everyone else.
Stick with me now. It doesn't have to be all bland. I recommend trying to substitute sweetened beverages with sparkling water, unsweetened coffee or green teas, or -- my personal favorite -- infusion water. Just add a few slices of lime or cucumbers to your water for a spa-like beverage. These can give you fun options without the additives or sugar.
What the science says about sugar substitutes
One prominent cohort scientists have examined is the CARDIA study, which recruited about 5,000 healthy adults without diabetes ages 18 to 30 during the mid-1980s from four U.S. cities. The study found that in the long term, diet beverages and sugar substitutes like aspartame and saccharin were linked to greater body mass intake and waist circumferences -- a well-studied predictor of insulin resistance -- over the subsequent 25 years of follow-up.
An abstract presented at the meeting of the American Society for Nutrition in May performed another analysis of the CARDIA cohort and showed that people with the highest intake of diet beverages were linked to a 129% greater probability of developing Type 2 diabetes compared with those who drank them the least -- even after adjusting for possible confounders like exercise, obesity and other aspects of diet quality. To be clear, these analyses don't prove causality, but the patterns raise concerns.
Which sugar substitute is healthiest?
Emerging data is telling us that not all sugar substitutes are created equal -- and that we still have to make sense of some conflicting data. Here's what to know about some common versions:
Aspartame: This is the artificial sweetener in many diet sodas and is classified as possibly carcinogenic to humans by the World Health Organization -- though the data has been somewhat varied.
Sucralose: Sucralose is also present in many "zero sugar" packaged foods. It has been found to increase blood flow to the hypothalamus, an area of the brain that helps manage appetite. Compared with table sugar, sucralose can increase feelings of immediate hunger. This has led some scientists to hypothesize that consuming sucralose could lead to overall increased calorie consumption. (By contrast, calorie restriction has been shown to improve insulin sensitivity.) Still, the studies don't all perfectly align. In the recent CARDIA analysis, researchers didn't find that sucralose intake led to higher rates of Type 2 diabetes.
Saccharin and stevia: A recent study in Cell found that several non-sugar sweeteners -- including saccharin, sucralose, aspartame and stevia -- disrupted the microbiome of healthy adults who did not otherwise consume them. It also found that sucralose and saccharin, in particular, also caused worsening of glucose tolerance.
Even though the data gives me pause, let me just clarify that the advice here isn't that people with Type 2 diabetes should use table sugar. No doubt, sugar substitutes are more helpful compared with table sugar for people with Type 2 diabetes. Just keep in mind that non-sugar sweeteners are not a win-win, and you should think of them as a treat -- not a staple of your diet.
How to plan meals with Type 2 diabetes
The advice around the best diet for Type 2 diabetes can feel murky. Should you adopt the Mediterranean diet? Low-carb? Plant-based?
The low-carbohydrate framework is recommended by the American Diabetes Association. This can be compatible with the Mediterranean diet, which involves eating whole grains, fruits, vegetables, healthy fats and minimal amounts of meat, and carries health benefits well beyond glucose tolerance. But this framework can also work with a plant-based or vegetarian diet or other low-carbohydrate diets.
To plan your meals, make half the plate a non-starchy vegetable, such as broccoli, spinach or Brussels sprouts. Then save a quarter of the plate for a lean protein like chicken, salmon or tofu. And finally, another quarter for healthier carbs like whole grain bread, fruit or low-fat yogurt (without added sugar). Check out this visual from the American Diabetes Association to help with planning.
Whatever diet you follow, take an approach that emphasizes higher protein and fiber intake, which are processed more slowly and evenly by the gut, and reduce consumption of highly processed carbohydrates, which otherwise would cause glucose spikes.
Is the keto diet good for people with Type 2 diabetes?
In 2022, researchers performed a head-to-head crossover study of the Mediterranean diet vs. a ketogenic diet for people with prediabetes and Type 2 diabetes. (The ketogenic diet involves eating very little carbohydrates and plenty of fats.)
Both diets did equally well controlling blood sugar and aiding weight loss. However, people had much more trouble sticking with the ketogenic diet long-term. This diet was also lower in some important nutrients like fiber and may increase the risk of heart disease, which is a serious problem for people with Type 2 diabetes.
The key is to find an eating pattern that will work for you in the long run. The goal is to maintain the pleasure of eating and to eat foods you love based on personal or cultural preferences, so speaking with a registered dietitian for more individual advice can help.
What I want my patients to know
Look out for non-sugar sweeteners in common ultra-processed foods. They're in everything, some of which may surprise you. Think shelf-stable bread, yogurt, canned soup and protein or snack bars.
And food labeling is so tricky. For instance, products that say "no artificial sweeteners" may, in fact, still be laden with steviol glycosides because that is, technically, a "natural" sweetener (it's also 200 to 400 times sweeter than table sugar).