Thanksgiving dinner is undeniably delicious, but it can also be overkill for many people. Consuming large portions of carb-rich sides and sweets can send blood sugar levels soaring, especially in those with diabetes and insulin resistance. Understanding what happens to your blood sugar during a traditional holiday meal can help you enjoy the day while staying mindful.
All foods affect your blood sugar, but the extent of their impact depends on factors like the food’s glycemic index (how quickly it raises your blood sugar), what the food is paired with, and individual blood sugar responses.
“Other than the turkey, the most popular dishes at Thanksgiving tend to be the ones with the greatest GI [glycemic index] and [glycemic load], since they’re simple carbohydrates,” Carolyn Jasik, MD, associate chief clinical officer for care solutions at Verily, told Health.
Foods that impact blood sugar the most are those that are high in carbs and low in fiber and protein, for example:
- Desserts: Pies, cakes, ice cream, and cookies
- High-carb sides: Mashed potatoes, stuffing, macaroni and cheese, candied yams, sweet potato casserole, and rice dishes
- Sweet drinks: Punch, sugary alcoholic drinks, and soda
- Breads: Rolls and sweet breads
High-protein, low-carb foods, like turkey, Brussels sprouts, broccoli, and other non-starchy vegetables, have little impact on blood sugar on their own, as long as they’re not topped with sugary sauces or paired with carb-rich sides.
“When you eat a large Thanksgiving meal, your body immediately goes to work,” Frank Dumont, MD, internal medicine physician at Virta Health, told Health.
Your body quickly breaks down carbohydrates into glucose, which is then absorbed into the bloodstream. In response to this increase in blood sugar, your pancreas releases insulin, a hormone that helps move glucose out of the blood and into your cells for immediate energy or into storage as glycogen and fat, helping bring blood sugar levels back down.
“If you are metabolically healthy, this works extremely well,” said Dumont. “Your body gets the energy it needs, and your blood sugar remains at a healthy level.” Even if you indulge in a larger, high-carb meal, your body can adapt and bring your blood sugar back down within a healthy range.
However, if you have metabolic dysfunction, such as high blood sugar or insulin resistance, this can make it more challenging for your body. When you have insulin resistance, your body stops responding to insulin, leading to chronically high insulin and blood sugar levels.
“If you have prediabetes or diabetes, even with the extra insulin, the sugar levels start to go above the normal range, and this can cause long-term damage to your body and even an immediate risk if blood sugar levels climb high enough,” said Dumont.
In a metabolically healthy person, blood sugar levels start to rise after you begin your meal, typically peak between 30-60 minutes after, and return to normal within 2 hours.
However, research shows that high–GI dishes, like many components of a traditional Thanksgiving dinner, raise blood sugar faster and more sharply than lower-GI meals. In other words, the more high-GI foods on your plate, the quicker and higher your blood sugar is likely to spike, especially if you have overweight or metabolic disease.
Additionally, in people with diabetes, blood sugar doesn’t come back down as quickly. Levels tend to stay higher for longer after a meal and may remain elevated even when fasted because the body has a harder time managing and clearing excess glucose.
Though most people can occasionally enjoy indulgent meals without any significant impact on health, it’s always best to make healthy choices whenever possible.
- Start with fiber-rich foods first: Consider starting with a green salad, green beans, or roasted Brussels sprouts. “Eating high-fiber, non-starchy vegetables at the beginning of a meal can help slow glucose absorption and lower peak blood sugar levels,” Grace Phelan, MS, RD, nutrition support coordinator at Tufts Medical Center, told Health.
- Pair carbs with protein, fiber, and healthy fats: “Carbs consumed after protein and fat allow glucose to enter the bloodstream more slowly, with a less steep peak,” said Jasik. For example, try eating turkey with your mashed potatoes, or add nuts to roasted sweet potatoes.
- Watch portion sizes of carb-dense sides: It’s best to stick to smaller portions of sweets and high-carb sides, like stuffing, rolls, mashed potatoes, and pies.
- Stay hydrated: “Just having more fluid in your stomach can help you avoid eating more than you should due to that ravenous, empty stomach feeling,” said Dumont. Enjoy high-carb beverages, like cider and sugary cocktails, with a meal or a high-protein appetizer to reduce their impact on blood sugar.
- Take a post-meal walk: Research shows that as short as a 10-minute walk can significantly reduce blood sugar levels.
- Look at the big picture: One holiday meal isn’t going to make or break your health. Your overall dietary pattern matters far more than a single Thanksgiving meal. Instead of stressing over one day, focus on long-term habits that truly impact health, like cutting back on added sugars, eating more whole foods, and staying active.
