Eating for metabolic health and balanced blood sugar is not the same as eating low-carb. Yes, carbohydrates become glucose when you eat them, and yes, extra glucose raises your blood sugar levels. But not all carbs are the same, and not all carbs lead to the large glucose spikes that we want to avoid for optimal metabolic health.
Foods like vegetables, fruits, and beans contain carbohydrates, and nixing them from your diet would mean missing out on some of the best sources of fiber and micronutrients. These nutrients are important for a healthy gut microbiome and powering countless physiological reactions that support optimal health and energy levels.
The carbs we want to avoid are added sugars and refined grain products—both dense sources of carbohydrates with minimal nutrients.
In addition to favoring healthy sources of carbohydrates, there are also ways you can buffer some of their potential negative metabolic effects in how you eat them and what you eat them with.
What are Carbohydrates?
Carbohydrates are a type of macronutrient found in certain foods and beverages. The other macronutrients are fats and proteins. Unless you’re intentionally following a very low carb diet like keto, you’ll likely eat all three as part of a healthy diet.
When someone refers to a particular food as a “carb,” it typically means it contains a higher proportion of carbs compared to fats and proteins, but it doesn’t necessarily contain only carbs (unless it’s some form of pure sugar).
Sugars, starches, and fiber are the main forms of carbohydrates in food. With the exception of fiber, carbohydrates are broken down in the body by digestive enzymes into monosaccharides, a.k.a. simple sugars. Most carbs are broken down into glucose, but, depending on the food, some yield fructose and galactose. Glucose is absorbed into the bloodstream via the intestines and serves as a primary fuel source for our cells.
You might also hear the terms “complex carbohydrates” and “simple carbohydrates.” Complex carbohydrates refer to longer, more complex carb molecules, including starches and fiber. Simple carbohydrates refer to simple carb molecules, or sugars.
Alone, these terms aren’t the most helpful for determining the healthfulness of a carb-containing food. Relative to other carbs, simple carbs are broken down and absorbed more rapidly by the body, and thus are more likely to spike blood sugar. But complex carbs in the form of starch can also elevate blood sugar. Fiber, on the other hand, slows digestion and helps buffer blood sugar spikes. All of this is why it’s important to look at both the total carbs as well as the sugar content and fiber content of a food.
What Types of Foods Contain Carbs?
Carbohydrates can be found in a wide range of foods, from highly processed fare devoid of meaningful nutrition to whole vegetables, fruits, beans, and grains that are rich in fiber and essential vitamins and minerals.
Typically, experts use a food's level of processing to differentiate between high- and low-quality carbs. But even among whole foods, there are better and worse choices when it comes to keeping blood glucose balanced.
If you’re aiming for stable blood sugar levels, choose non-starchy vegetables such as broccoli, brussels sprouts, leafy greens, cauliflower, cucumber, mushrooms, green beans, and cabbage, and lowe-sugar fresh fruits such as berries and kiwis.You can also go for smaller portions of moderate-sugar fruits that contain a decent amount of fiber, like apples and oranges.
Whole foods that are higher in carbohydrates and more likely to impact blood sugar include starchy vegetables such as butternut squash, sweet potatoes, beets, corn, and parsnips; beans and lentils; high-sugar fruits such as bananas, mangoes, and grapes; and whole grains such as quinoa, millet, teff, buckwheat, farro, oats, and rice. These can all be a part of a nutritious diet, Atlas says, but you may need to be more mindful of your portion size, what you pair them with and how they impact your blood sugar.
Lower-quality carbs that are best avoided include candy, soda, juice, sweeteners (table sugar, honey, maple syrup, etc), and foods made from grain-based flours (crackers, cookies, breads, pastas, cereal). All of these can be considered “acellular carbs, meaning they contain carbs that have been broken out of their natural fiber cell, which speeds digestion and makes them more likely to spike blood sugar.
To recap, it might help to look at it this way:
- “Always” carbs = non-starchy veggies and low-sugar fruits like berries
- “Maybe” carbs = starchy veggies and legumes, higher-sugar fruits, whole grains
- “Avoid” carbs = sodas, juices, sweeteners, flour-based products, and other highly-processed foods
Tips for Eating Carbs to Optimize Nutrition and Keep Blood Sugar Steady
Carb-containing foods can be a wonderful addition to a healthy diet, but the exact amount of carbs you should eat is not one-size-fits-all—age, sex, physical activity, body composition goals, and other factors can all play a role. That’s why giving a specific recommendation for daily carbohydrate intake can be tricky. In general, though, “it’s fair to say that 40% or less of daily calories from carbs is beneficial for most, and I often lean towards a much tighter range of 30% or less. This tighter range works out to consuming less than 150 grams of carbohydrates on a 2,000 calorie per day diet; and if you’re following an ultra-low-carb diet like keto, cap your intake at around 25 to 50 grms of carbs per day.
1. Cut out added sugars, refined grains, and liquid carbs
When it comes to severe blood sugar spikes, these are the top three offenders—so start here if you need help prioritizing where to scale back.
- Added sugars—even from natural sources like honey and maple syrup—are a poor source of micronutrients and can rapidly elevate blood sugar.
- Breads, pastas, crackers, desserts, and cereals made with refined grain- based flours. These have had their fibrous components removed (or ground up, in the case of whole-grain flours), which promotes the rapid breakdown of carbs absorption of glucose into the bloodstream.
- Liquid carbs, including juice, sodas, and sports drinks, are an obvious place to cut back, but be smart about alcohol, too. A 12-ounce beer has around 12 grams of carbs, a 5-ounce glass of wine contains 4 grams, and hard liquor, while relatively low in carbs, is often combined with sugary sodas and juice. Plus, research suggests that no amount of alcohol is good for you (contrary to popular belief that moderate drinking is healthy). Try low-carb alternative like a seltzer mocktail or bitters and soda.
2. Opt for whole or minimally processed carb foods
Unlike heavily processed fare, whole foods retain their fiber and micronutrients—so even if they deliver some carbs, they’re at least packaged with beneficial compounds that help buffer blood sugar spikes and support metabolic health. Nutritious options include:
- Leafy greens (spinach, kale, arugula, bok choy, swiss chard)
- Broccoli
- Brussels sprouts
- Cauliflower
- Cabbage
- Bell peppers
- Carrots
- Asparagus
- Green beans
- Mushrooms
- Avocado
3. Consider your unique response to carbs
While the recommendations above generally hold true, everyone has a somewhat unique response to the same carb-containing foods—so, for example, you could experience large swings in blood sugar even with whole foods like beans, apples, or oats, while your friend does not. Using a continuous glucose monitor (CGM) is the easiest way to evaluate your response to specific foods and modify their intake accordingly, but you can also check blood sugar after meals with an over-the-counter fingerstick test.
4. Don’t eat carbs alone
As a general rule, when carbohydrates are the primary macronutrient in a food or meal, pair them with protein and fat to slow digestion and minimize post-meal blood sugar elevations. These two macros signal the release of hormones in the gut that slow gastric emptying, thereby reducing the rate at which glucose enters the bloodstream.
This also works with desserts. Try pairing a piece of dark chocolate with some nut butter, or make baked goods with collagen or protein powder. Or, if a treat is better on its own, eat it right after a meal containing protein, fiber, and fat as opposed to waiting.
5. Minimize carbs at night
Your body is generally more insulin sensitive (i.e. your cells are more efficient at taking up glucose from the bloodstream)in the morning. So consuming a carb-rich food earlier in the day—say, a banana after lunch rather than dinner—will lead to a milder blood glucose response.
At dinner, aim for mostly or all low-carb foods, such as a protein-rich salad or meat with a side of non-starchy veggies. And try to stop eating a few hours before bed.
