Many studies have confirmed their ability to lower insulin levels and increase insulin sensitivity, compared to other diets (5, 6, 7, 8, 9).
People with health conditions characterized by insulin resistance, such as metabolic syndrome and polycystic ovary syndrome (PCOS), may experience a dramatic lowering of insulin with carb restriction.
In one study, individuals with metabolic syndrome were randomized to receive either a low-fat or low-carb diet containing 1,500 calories.
Insulin levels dropped by an average of 50% in the low-carb group, compared to 19% in the low-fat group (10).
In another study, when women with PCOS ate a lower-carb diet containing enough calories to maintain their weight, they experienced greater reductions in insulin levels than when
they ate a higher-carb diet (11). 2. Take Apple Cider Vinegar
Apple cider vinegar has been credited with preventing insulin and blood sugar spikes after eating.
This has been shown to mainly occur when vinegar is taken with high-carb foods (12, 13, 14).
A small study found that people who took about 2 tablespoons (28 ml) of vinegar with a high-carb meal experienced lower insulin levels and greater feelings of fullness 30 minutes after the meal (14).
Researchers believed this effect was partly due to vinegar’s ability to delay stomach emptying, leading to a more gradual absorption of sugar into the bloodstream (15).
Bottom Line: Vinegar may help prevent high insulin levels after you consume meals or foods high in carbs.
3. Watch Portion Sizes
Although the pancreas releases different amounts of insulin depending on the type of food you eat, eating too much of any food at one time can lead to hyperinsulinemia.
In one study, insulin-resistant obese people who consumed a 1,300-calorie meal had twice the increase in insulin as lean people who consumed the same meal.
They also experienced nearly twice the increase in insulin as obese people who were considered “metabolically healthy” (16).
Consuming fewer calories has consistently been shown to increase insulin sensitivity and decrease insulin levels in overweight and obese individuals, regardless of the type of diet they consume (17, 18, 19, 20, 21, 22, 23).
One study looked at different weight loss methods in 157 people with metabolic syndrome.
The researchers found that fasting insulin levels decreased by 16% in the group that practiced calorie restriction and 12% in the group that practiced portion control (23).
Bottom Line: Reducing calorie intake by portion control or counting calories can lead to lower insulin levels in overweight and obese people with type 2 diabetes or metabolic syndrome.
4. Avoid All Forms of Sugar
Sugar may very well be the most important food to stay away from if you’re trying to lower your insulin levels.
In one study where people overate either candy or peanuts, the candy group experienced a 31% increase in fasting insulin levels, compared to a 12% increase in the peanut group (24).
In another study, when people consumed jams containing high amounts of sugar, their insulin levels rose significantly more than after consuming low-sugar jams (25).
Fructose is found in table sugar, honey, high-fructose corn syrup, agave and syrup. Consuming large quantities of it promotes insulin resistance, which ultimately drives insulin levels higher (26, 27, 28).
One study found that people had similar insulin responses after consuming 50 grams of table sugar, honey or high-fructose corn syrup every day for 14 days (29).
In another study, overweight people who added high-sugar foods to their usual diet experienced a 22% increase in fasting insulin levels.
In contrast, the group who added artificially sweetened foods to their usual diet experienced a 3% decrease in fasting insulin levels (30).
Bottom Line: A high intake of sugar in any form has been shown to increase insulin levels and promote insulin resistance.
5. Exercise Regularly
Engaging in regular physical activity can have powerful insulin-lowering effects.
Aerobic exercise appears to be very effective at increasing insulin sensitivity in people who are obese or have type 2 diabetes (31, 32, 33, 34).
One study compared two groups. One performed sustained aerobic exercise, and the other performed high-intensity interval training.
The study found that although both groups experienced improvements in fitness, only the group that performed sustained aerobic activity experienced significantly lower insulin levels (34).
There’s also research showing that resistance training can help decrease insulin levels in older and sedentary adults (35, 36).
Combining aerobic and resistance exercise seems to be the most effective and has been shown to most greatly affect insulin sensitivity and levels (37, 38, 39).
In a study of 101 breast cancer survivors, those who engaged in a combination of strength-training and endurance exercise for 16 weeks experienced a 27% reduction in insulin levels
Bottom Line: Aerobic exercise, strength training or a combination of both may help increase insulin sensitivity and lower your levels.
6. Add Cinnamon to Foods and Beverages
Cinnamon is a delicious spice loaded with health-promoting antioxidants.
Studies in healthy people and those with insulin resistance suggest that taking cinnamon may enhance insulin sensitivity and decrease insulin levels (40, 41, 42).
In one study, healthy people who consumed about 1.5 teaspoons of cinnamon in rice pudding had significantly lower insulin responses than when they ate rice pudding without cinnamon (41).
In another small study, young men who consumed a high-sugar drink after taking cinnamon for 14 days experienced lower insulin levels than when they consumed the drink after taking a placebo for 14 days (42).
It’s important to note that not all studies have found that cinnamon lowers your levels or increases insulin sensitivity. Cinnamon’s effects may vary from person to person (43, 44).
However, including up to one teaspoon (2 grams) per day may provide other health benefits, even if it doesn’t reduce your levels significantly.
Bottom Line: Some studies have found that adding cinnamon to foods or beverages lowers insulin levels and increases insulin sensitivity.
However, research in animals and humans has found that consuming them regularly can lead to several health problems.
These include high insulin levels and weight gain (45, 46, 47).
Furthermore, refined carbs have a high glycemic index.
The glycemic index (GI) is a scale that measures a specific food’s capacity to raise blood sugar. Glycemic load takes into account a food’s glycemic index, as well as the amount of digestible carbs contained in a serving.
Several studies have compared foods with different glycemic loads to see if they affected insulin levels differently.
They found that eating a high-glycemic load food raises your levels more than eating the same portion of a low-glycemic load food, even if the carb contents of the two foods are similar (48, 49, 50).
In one study, overweight people followed one of two unrestricted-calorie diets for 10 weeks. After a test meal, the high-GI group had higher insulin levels than the low-GI group (51).
Bottom Line: Replacing refined carbs, which are digested and absorbed quickly, with slower-digesting whole foods may help lower insulin levels.
8. Avoid Sedentary Behavior
In order to reduce insulin levels, it’s important to live an active lifestyle.
One study of over 1,600 people found that those who were the most sedentary were nearly twice as likely to have metabolic syndrome as those who performed moderate activity at least 150 minutes per week (52).
Other studies have shown that getting up and walking around, rather than sitting for prolonged periods, can help keep insulin levels from spiking after a meal (53, 54).
A 12-week study in middle-aged sedentary women found that the women who walked for 20 minutes after a large meal had increased insulin sensitivity, compared with women who didn’t walk after a meal.
In addition, the walking group became more fit and lost body fat (55).
Another study looked at 113 overweight men at risk of type 2 diabetes.
The group who took the most steps per day had the greatest reduction in insulin levels and lost the most belly fat, compared to the group who took the lowest number of steps daily (56).
Bottom Line: Avoiding prolonged sitting and increasing the amount of time you spend walking or doing other moderate activities can reduce insulin levels.
It absorbs water and forms a gel, which slows down the movement of food through the digestive tract. This promotes feelings of fullness and keeps blood sugar and insulin from rising too quickly after a meal (61, 62, 63, 64).
One observational study found women who ate the highest amount of soluble fiber were half as likely to be insulin resistant as women who ate the least amount of soluble fiber (65).
Soluble fiber also helps feed the friendly bacteria that live in your colon, which may improve gut health and reduce insulin resistance.
In a six-week controlled study of obese older women, those who took flaxseed experienced greater increases in insulin sensitivity and lower insulin levels than women who took a probiotic or placebo (66).
Overall, fiber from whole foods appears to be more effective at reducing insulin than fiber in supplement form, although results are mixed.
One study found that a combination of whole food and supplemental fiber lowered insulin levels the most. Meanwhile, another found that insulin decreased when people consumed black beans but not when they took a fiber supplement (67, 68).
Bottom Line: Soluble fiber, especially from whole foods, has been shown to increase insulin sensitivity and lower insulin levels, particularly in people with obesity or type 2 diabetes.
11. Lose Belly Fat
Belly fat, also known as visceral or abdominal fat, is linked to many health problems.
Carrying too much fat around your abdomen promotes inflammation and insulin resistance, which drives hyperinsulinemia (69, 70, 71).
Studies have shown that decreasing belly fat leads to increased insulin sensitivity and lower insulin levels (72, 73, 74).
Interestingly, one study found that people who lost abdominal fat retained the benefits for insulin sensitivity, even after regaining a portion of the belly fat back (75).
Unfortunately, people with high insulin levels often find it very difficult to lose weight. In one study, those with the highest levels not only lost weight less rapidly but also regained the most weight later on (76).
Several studies suggest it may help fight insulin resistance (77, 78, 79, 80, 81, 82).
In one study, people with high insulin levels who took green tea extract experienced a small decrease in insulin over 12 months, while those who took a placebo had an increase (81).
In a detailed analysis of 17 studies, researchers reported that green tea was found to significantly lower fasting insulin levels in studies considered the highest quality (82).
However, not all high-quality studies have shown that green tea reduces insulin levels or increases insulin sensitivity (83, 84).
Bottom Line: Several studies have found that green tea may increase insulin sensitivity and decrease insulin levels.
13. Eat Fatty Fish
There are many reasons to consume fatty fish like salmon, sardines, mackerel, herring and anchovies.
They provide high-quality protein, and are by far the best sources of long-chain omega-3 fats, which have all sorts of benefits.
Studies have shown they may also help reduce insulin resistance in people with obesity, gestational diabetes and PCOS (85, 86, 87, 88).
One study in women with PCOS found a significant 8.4% decrease in insulin levels in a group who took fish oil, compared to a group who took placebo (87).
Another study in obese children and adolescents showed that taking fish oil supplements significantly reduced insulin resistance and triglyceride levels.
Bottom Line: The long-chain omega-3 fatty acids found in fatty fish may help reduce insulin resistance and insulin levels.
14. Get the Right Amount and Type of Protein
Consuming adequate protein at meals can be beneficial for controlling your weight and insulin levels.
In one study, overweight older women had lower insulin levels after consuming a high-protein breakfast compared to a low-protein breakfast. They also felt fuller and ate fewer calories at lunch (89).
However, protein does stimulate insulin production so that your muscles can take up amino acids. Therefore, eating very high amounts will lead to higher insulin levels.
In addition, some types of protein appear to cause greater insulin responses than others. One study found that whey and casein protein in dairy products raised insulin levels even higher than bread in healthy people (90).
However, the insulin response to dairy proteins may be somewhat individual.
One recent study found that insulin levels increased similarly in obese men and women after meals containing beef or dairy (91).
Another study in obese adults showed a high-dairy diet led to higher fasting insulin levels than a high-beef diet (92).
Bottom Line: Avoiding excessive amounts of protein, especially dairy protein, can help prevent insulin levels from rising too high after meals.
Take Home Message
High insulin levels can lead to many health problems.
Taking steps to increase your insulin sensitivity and decrease your insulin levels may help you lose weight, lower your risk of disease and increase your quality of life.