Everything You Need to Know about Beans and the Keto Diet
Written by Matt Koulas
on November 13, 2019
The ketogenic diet has fairly clear-cut rules when it comes to food choices – eat foods that are high in fat and low in carbohydrates.
The rules about whether beans belong on a keto-friendly diet are somewhat murkier.
Beans are an important part of a healthy diet. They belong to a class of plant foods known as legumes, which also includes lentils and peas. The U.S. Department of Agriculture (USDA) ChooseMyPlate guidelines classify beans as both a vegetable and a plant-based protein source. The USDA recommends everyone, even those who eat meat, poultry and fish regularly, consume legumes.
The big problem with beans, though, is that they tend to be high in carbohydrates, which is tightly restricted on the low-carb keto diet.
Carbs and the Keto Diet
Carbohydrates are a group of organic compounds found in living tissue. In fact, almost all living things contain some carbohydrates, as carbohydrates play an important role in immune system, fertilization, blood clotting, and human development.
Your body absorbs carbohydrates from the foods you eat. There are three main types of carbohydrates in food: sugar, starch and dietary fiber.
Some foods contain more carbohydrates than do other foods, and some high-carbohydrate foods are healthier than are others. Unhealthy carbs include pancakes, bread, sugary drinks, corn chips, and candy. Healthy carbohydrates include whole grains, fresh fruits and vegetables, nuts, seeds, and beans.
When you eat carbohydrates, particularly the sugary carbs, your blood sugar rises. Your pancreas then releases insulin to bring your blood sugar, also known as blood glucose, down. Insulin “unlocks” muscle, fat and other tissue cells so that they can absorb glucose from the bloodstream. Unlocking muscle cells will allow your body to use carbohydrates as energy to run, jump, and do other physical activities. Unlocking fat cells allows your body to store excess energy as fat.
Insulin also stimulates your liver to store glucose in the form of glycogen. We’ll talk more about glycogen in a moment.
Using carbohydrates as energy
The human body uses carbohydrates as the primary source of energy. When deprived of carbohydrates, the body looks for other forms of energy. The liver releases its store of glycogen, for example, which the body can use as fuel.
The stores of glucose run out eventually, and the body starts breaking down fat. As it breaks down, fat releases fatty acids that the body changes into ketones. In a process known as ketogenesis, the tissues begin to use these ketones as energy. Ketones will circulate in the body, and the body will continue to burn fat for energy, as long as you avoid eating carbohydrates. Nutrition experts refer to this as a state of ketosis.
Keeping the body in ketosis by starving it of carbohydrates is the foundation of the ketogenic diet. Eating beans may throw your body out of ketosis by introducing carbs as a form of energy. You need to ensure you maintain a high level of fat intake.
Carb restrictions on a low-carb diet
Everyone has different requirements when it comes to carb restrictions and remaining in ketosis, but keto diets generally limit carb intake to 15 – 30 grams of net carbohydrates per day, or 5 to 10 percent of your total calories. If you are an active person who exercises four to five times a week, you can probably consume more carbs without any repercussions. If you lead a sedentary lifestyle or are overweight, you should keep your carbohydrate intake as low as possible.
To keep you in ketosis, your ketogenic diet should primarily consist of food that is high in fats, moderate in proteins, and very low in carbohydrates. Specifically, your diet should consist of 55 to 60 percent fat, 30 to 35 percent protein, and 5 to 10 percent carbohydrates. This works out to 20 to 50 grams of carbohydrates a day on a 2000 calorie/day diet. Considering just one 10” flour tortilla has 36 grams of carbohydrates, the keto diet does not provide a lot of wiggle room when it comes to carbs.
Here is how beans work into the equation.
Humans started cultivating beans and other legumes about 25,000 years ago, according to The Bean Institute. With more than 400 edible varieties grown on every continent except Antarctica, beans are now a food staple in every culture. Beans are easy to grow Some of the most commonly eaten beans in the United States include navy, pinto, black, cranberry, Great Northern, dark red kidney, white kidney, light red kidney, pink, and small red beans.
Beans are nutritious
Beans are a popular staple because they are high in fiber and rich in nutrients. Dry beans contain both soluble and insoluble fiber, for example. Soluble fiber can help lower your blood cholesterol levels by binding to the cholesterol in food before your digestive tract has a chance to absorb it.
The insoluble fiber in beans helps keep bowel movements regular by attracting water to the stool inside the intestines. Insoluble fiber can help reduce constipation, which is an unpleasant and common side effect of the keto diet.
Dry beans are a good source of a number of important vitamins and minerals. Beans contain the mineral potassium, for example, which promotes healthy blood pressures. These legumes contain thiamin, also known as vitamin B1, which plays a critical role in energy metabolism and the function, growth, and development of body cells. The folate (folic acid) in beans helps your body make DNA and other genetic material, and is important to the production of red and white blood cells in your bone marrow. Beans also contain riboflavin, which is important to energy production, cellular function, and the metabolism of the fat included in the keto diet. The vitamin B6 in beans plays a role in more than 100 enzyme reactions, most of which are involved in the metabolism of protein.
Beans contain important minerals too, such as iron, copper, phosphorus, manganese and magnesium. The iron in beans is an essential part of hemoglobin, which is a protein in red blood cells that helps transfer oxygen in the blood to the various tissues of the body. Copper helps your body to metabolize iron; both copper and magnesium are involved in energy production. Among their many jobs, phosphorus and manganese play an important role in how your body uses carbohydrates and other nutrients.
Beans are inexpensive
Protein can be the one of the most expensive components of your diet; beans are one of the least expensive plant-based proteins available. In fact, pound per pound, beans are among the most affordable of all food components.
Price of beans, according to the USDA:
- Canned pinto beans: $0.80 per pound and $0.48 per cup
- Dried pinto beans: $1.09 per pound and $0.17 per cup
- Canned great northern beans: $0.87 per pound and $0.52 per cup
- Dried great northern beans: $1.59 per pound and $0.26 per cup
- Canned kidney beans: $0.86 per pound and $0.51 per cup
- Dried kidney beans: $1.69 per pound and $0.27 per cup
- Canned pinto beans: $0.80 per pound and $0.48 per cup
- Dried pinto beans: $1.09 per pound and $0.17 per cup
- Canned black beans: $0.95 per pound and $0.56 per cup
- Dried black beans: $1.40 per pound and $0.24 per cup
Pound for pound, protein-rich beans are vastly less expensive than meat. The National Chicken Council estimates the cost of beef, pork and chicken to be an average of $5.95, $3.70 and $1.90 respectively in 2019.
Beans are convenient and versatile
Beans have a place on the plate for nearly every meal, from black bean breakfasts to a Tuscan white bean skillet for dinner and coconut red bean pudding for dessert. Canned beans are especially easy to add to almost any dish – just empty the can into a pot or casserole and bring to temperature.
Drawbacks to eating beans
There are some disadvantages to eating too many beans. Consuming beans can cause flatulence, for example, especially if you are not used to consuming high-fiber foods. Some types of beans cause more gas than other beans. Research shows that pinto beans and baked beans cause more flatulence than black-eyed peas.
Beans may also contain “anti-nutrients” that can prevent your body from absorbing certain nutrients from food. Animals and many types of plant foods contain anti-nutrients. These anti-nutrients protect plants from bacterial infections and insects. Beans and other legumes contain lectins that can interfere with the absorption of calcium, iron, phosphorus, and zinc. Phytates, also known as phytic acid, can prevent your digestive tract from absorbing iron, zinc, magnesium, and calcium. Tannins in beans can decrease the absorption of iron, and the saponins in legumes can interfere with overall nutrient absorption.
Some anti-nutrients, such as lectin and saponins in legumes, may cause leaky gut. Also known as increased intestinal permeability, leaky gut is digestive condition that allows bacteria and toxins to “leak” through the intestinal walls.
Researchers have not yet established how many nutrients are lost due to the anti-nutrients in beans, and the effects anti-nutrients varies between people based on their metabolism and how they prepare the beans.
Consumers can remove or deactivate many of the anti-nutrients, such as phytates and lectins, by soaking, sprouting, or boiling the beans before they eat them. Soaking beans overnight can remove as much as 80 percent of the phytates.
The Problem with Beans on a Keto Diet
So, with everything that beans have going for them, why are they not part of a keto diet?
While beans are versatile, convenient, nutritious, inexpensive and delicious, their high carb count can make them tough to fit into a low-carb keto diet. Eating too many beans can even pull you out of ketosis. Eating the wrong kinds of beans can also cause your body to start burning sugar instead of fat again.
So how many carbohydrates are in beans? It depends on the type.
Carb counts for one cup of cooked beans:
- Black beans: 40.8 grams
- Pinto beans: 44.8 grams
- Garbanzo beans (also known as chickpeas): 45 grams
- Kidney beans: 40.4 grams
- Red beans: 120 grams
Beans to Avoid and Beans to Include Very Sparingly
There are some specific beans you should avoid while on a keto diet, such as:
- Baked beans
- Garbanzo beans
- Lima beans
- Pinto beans
- Black beans
A 1-cup serving of these beans can use up your entire day’s worth of carbohydrates. When integrating these beans, it's best to use at most a half-cup serving to preserve available carbs for later in the day.
Some beans may be acceptable on a keto diet because they have fiber and other constituents that lower the amount of carbohydrates the beans actually provide to your body.
Nutrition experts categorize carbohydrates in terms of total carbs and net carbs. Total carbs include all of the different types of carbohydrates in a meal, including indigestible fiber, while net carbs include only the carbohydrates your body can absorb and convert into glucose. For example, a bean that contains 30 grams of total carbohydrates and 7 grams of fiber provides only 23 grams of net carbohydrates (30 – 7 = 23).
While most beans are off-limits on a keto diet, you can eat a few types of beans in moderation. For example, a cup of green beans contains only 9.8 grams of total carbs and 4 grams of dietary fiber for a skinny 5.8 grams of net carbs. Edamame, a type of soybean, has only 11.5 grams of total carbs and 5.7 grams of dietary fiber. A cup of lima beans contains 39.3 grams of total carbohydrates, and the 7 grams of fiber reduces the net carbohydrates to right about 33 grams of net carbs.
Low-carb Bean Alternatives for the High-Fat Keto Diet
Because calculating net carbs can be confusing, and because making a mistake can ruin ketosis, many people on the keto diet avoid beans altogether. Quitting beans “cold turkey” can be tough, though, as beans play such an important role in cuisine. Fortunately, you can incorporate several low-carb bean alternatives into your keto diet plan.
Beanless refried beans
Beanless refried beans create the taste and texture of refried beans without the beans or the carbs. This dish uses eggplant or zucchini, bacon and spices – top with optional cheese or sour cream for an authentic south-of-the-border flavor.
While peas are legumes, most peas contain about half the carbohydrates as beans. A cup of green peas contains only 21 grams of carbs, for example. Green peas are also an excellent source of vitamin A, vitamin K and protein. Peas work well as bean replacements in chili, salads and curry, but due to their distinct flavor, peas may not work well in many other bean-based dishes.
Lentils are also legumes with a total carb count of 40 grams, but they contain 16 grams of fiber, which brings the net carbohydrates down to manageable levels.
Enoki mushrooms resemble bean sprouts and have a texture similar to cooked beans, making them a great substitute for beans. One cup of sliced enoki mushrooms has only 24 calories and a mere 5 grams of carbs. Enoki mushrooms are also a great source of vitamins and minerals, such as iron, magnesium, phosphorus, potassium, and B vitamins. Enoki mushrooms are available fresh and canned, which make them easy to add to soups, salads and many other dishes.
Try buttery macadamia nuts, protein-rich almonds, or sweet pecans, which are chock full heart healthy vitamins but light on the carbohydrates.
A number of vegetables can mimic the taste and texture of beans without the burden of high carbohydrates. Try diced mushrooms, chopped zucchini or riced cauliflower as bean replacements.
When to Avoid Beans on a Keto Diet
In general, you should avoid beans as much as possible while on a keto diet. Avoiding beans and other foods high in carbohydrates is especially important during the first few weeks at the beginning stages of your diet, when your body is first transitioning from sugar-burning mode to fat-burning mode. Skipping the beans will help your body get into ketosis and stay there.
Everyone’s body is different, which means your system may process the carbohydrates in beans differently than someone else’s body. Once your body has adapted to burning fat instead of sugar, you may be able to handle a small serving of beans without being kicked out of ketosis.
Beans can have a place on the ketogenic diet plate, but they have to be the right kinds of beans, eaten only in moderation, and consumed only when substitutions are not available.
Author: Lynn Hetzler
|Lynn Hetzler has been a leading medical and nutrition writer for more than 20 years. She regularly publishes content for doctors and other medical professionals at Multibriefs, NursesUSA, and other high profile industry publications.|
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