1/3 of Americans born in 2000 or later are expected to develop type 2 diabetes. Diabetes leads to other complications such as blindness, neuropathy, amputations, arthritis, and premature death. (R) Maintain healthy blood sugar levels is crucial for maintaining a health body.
Quick Guide to Controlling Blood Sugar
Note: Check with your doctor before trying of the diet and lifestyle changes discussed here.
- Eat more vegetables
- Consume antioxidant rich foods
- Eat more nuts
- Eat little to no refined/processed carbohydrates; if you do, keep it to a minimum and pair it with lots of high fiber foods and/or lean protein
- Eat whole grains instead of refined grains
- Consider reducing how many carbohydrates you eat
- Eat a salad at least once a day with lunch or dinner
- Increase intake of soluble and insoluble fiber
- If you have an issue with food moving too fast through your digestive system, focus on consuming more soluble fiber and don’t drink much liquid with your meals (a couple sips of water shouldn’t hurt)
- Make your own salad dressing with olive oil and vinegar
- Add cinnamon to foods
- Consume moderate amounts of lean protein
- Lose weight if you have excess
- Lose visceral (intraabdominal) fat (you can’t target visceral fat, so lose fat in general)
- Don’t be sedentary
- Exercise once a day
- Consider consuming 1 alcoholic beverage before a meal (red wine is best)
- Sleep well and long enough
- Consume adequate amounts of dietary chromium
Americans typically eat a highly processed, calorie rich, and nutrient-depleted diet, which causes high spikes in blood glucose and lipids after eating (postprandial). The high blood sugar and triglycerides increases free radical generation and oxidative stress, which leads to inflammation, and negatively affects cardiovascular function and health. Inflammation is an important risk factor for many diseases, including diabetes, heart disease, and Alzheimer’s.
A diet that contains moderate amounts of lean protein, healthy fats, and minimal amounts of processed carbohydrates and saturated and trans fats will improve the blood sugar spike after eating a meal, which in turn will lower inflammation. (R)
Here is a basic understanding of how carbohydrate metabolism works. When you eat carbohydrates, they are digested and broken down to either glucose, fructose, and/or galactose. If the carb you eat is already in one of those forms of monosaccharides (meaning single sugar), then it’s digested as far as it needs to. As these monosaccharides are absorbed into the blood stream, blood sugar levels rise. This triggers the pancreas to produce and release insulin. Insulin is the hormone that helps move the sugar from the blood and into cells, which is where we want it to go. Insulin binds to the insulin receptor, some magic happens in the cell, which causes glucose transporter-4 (GLUT4) to move from the inside of the cell the cell surface. GLUT4 then moves glucose from the blood and into the cell, lowering blood glucose levels. The blood sugar is used for energy and excess is stored for energy in the form of glycogen (glycogenesis), and/or it is converted to fat (lipogenesis).
In between meals, blood sugar levels begin to fall. Insulin levels decrease, and the pancreas is signaled to produce and release the hormone glucagon. Glucagon is the hormone that tells the liver to release stored glucose (glycogenolysis) as well as produce and release glucose from precursors (gluconeogenesis), which helps to maintain blood glucose and prevent hypoglycemia. (R)
Eating lots of processed carbohydrates can trigger large spikes in blood sugar and insulin, which can lead to reactive hypoglycemia. Eating a lot of processed carbohydrates also increases visceral fat, which increases insulin resistance and inflammation, as well as increases the risk for diabetes and cardiovascular disease. It’s important to understand that lower post-prandial glucose levels lowers inflammation. (R)
The quantity of carbohydrates also makes a difference. Eating a small amount of white rice won’t have a huge impact on blood glucose, so complete avoidance of processed carbohydrates probably isn’t needed. Also, just because something is low glycemic, such as beans, doesn’t mean you can eat a ton of them. Eating a bunch of low glycemic carbohydrate foods in one meal will cause a large blood sugar spike. (R)
Insulin resistance causes insulin and blood glucose levels to remain elevated for long periods of time. (R) With insulin resistance, it gets harder to move GLUT4 to the cell surface, so more glucose stays in the blood.
Eating too many calories and not exercising will lead to increased weight gain and visceral fat, which are all major risk factors for insulin resistance and type 2 diabetes. Just being overweight increases the risk of developing type 2 diabetes. (R)
Weight loss has been shown to decrease fasting glucose and insulin levels, as well as improve insulin sensitivity. (R)
Insulin resistance is the cornerstone of type 2 diabetes, and is characterized by an impaired ability of insulin to decrease blood glucose levels. (R)
The cause of insulin resistance is relatively not well understood, but one cause may be excess accumulation of fat in muscle cells. (R)
Increased levels of plasma free fatty acids is associated with insulin resistance. Insulin normally inhibits the release of free fatty acids (lipolysis), but in persons with insulin resistance, insulin has a harder time impairing lipolysis, leading to elevated levels of free fatty acids. Chronically elevated plasma free fatty acids can lead to insulin resistance, because too much free fatty acids enter the muscle cells and impair insulin signaling. The excess fat in muscle cells could be caused by elevated plasma free fatty acids and/or an impaired ability to oxidize and utilize fat in the muscle cells for energy. This means that you could have normal plasma free fatty acid levels, but be at an increased risk of insulin resistance if the muscle cells have a hard time oxidizing fats (mitochondrial defect). (R)
Diabetes and Prediabetes
Type 1 diabetes is when the body cannot produce insulin and release it from the pancreas. Type 2 diabetes occurs from insulin resistance as well as an insufficient production and secretion of insulin. Type 2 diabetes represents about 90-95% of diabetes cases, and therefore is much more common than Type 1 diabetes. Diabetes can also occur from genetic defects, pancreatic disease, surgery, infections, drugs, chemicals, and even pregnancy (gestational diabetes). (R)
Markers Indicating Diabetes (R)
Hemoglobin A1c (HbA1c) is a marker that represents overall glycemic control over a 12 week time period. (R)
- Glycated hemoglobin A1c ≥ 6.5%
- Fasting plasma glucose ≥126 mg/dl (7.0 mmol/l)
- 2 hour plasma glucose ≥200 mg/dl (11.1 mmol/l) after ingestion of 75 g of glucose (oral glucose tolerance test)
- Random plasma glucose ≥ 200 mg/dl (11.1 mmol/l)
*You can pick up a glucometer at your local pharmacy to check blood glucose levels.
Markers Indicating Prediabetes (R)
- HbA1c of 5.7-6.4%
- Fasting plasma glucose 100–125 mg/dl (5.6–6.9 mmol/l)
- 2 hour oral glucose tolerance test 140–199 mg/dl (7.8–11.0 mmol/l)
Glycemic Index and Glycemic Load
Consuming high-glycemic-index, low-fiber foods increases the risk of diabetes and cardiovascular disease. (R)
Low glycemic foods have been shown to help maintain healthy blood sugar levels in persons with type 2 diabetes.
- Low: 55 or less
- Medium: 56-69
- High: 70-100
Glycemic load may be more important than glycemic index. The glycemic load takes into account both the amount of carbohydrate a food contains, as well as how it affects blood sugar levels.
- Low: 10 or less
- Medium: 11-19
- High: 20 or more
One large meta-analysis found that people who consume a low glycemic load diet have a lower risk of developing type 2 diabetes than those who consume a high glycemic load diet. (R)
Harvard Health has a good list of foods and their glycemic index and glycemic load here.
Focus on consuming lower glycemic foods.
Fiber slows gastric emptying, which can be an important tool to prevent large blood sugar spikes. (R)
An increase in dietary fiber intake significantly improves fasting blood glucose and HbA1c levels. (R)
Our bodies cannot digest fiber, but the bacteria in our gut can. Fiber provides many health benefits to us. I am mostly focusing on how it affects blood sugar in this article, but there are other ways in which fiber can help promote a healthy body.
Fiber is found in plant foods, and there are two types: soluble and insoluble. Soluble fiber dissolves in water, is known as the gel-forming fiber, and is found in foods such as oats, beans, oranges, sweet potatoes, and many other foods. Insoluble fiber doesn’t dissolve in water easily, is more “rough”, and is known as the bulk forming fiber. Insoluble fiber is found in foods such as whole grains, kale, and beans. The fibers aren’t found in foods by themselves. Instead, foods that contain fiber usually contain both soluble and insoluble fiber. However, a lot of foods tend to be higher in one or the other.
Fiber increases satiety, and keeps us feeling fuller for longer. Soluble fiber has been shown to reduce the postprandial glucose response. The gel-forming properties of soluble fiber slows gastric emptying, increases gut transit time (takes longer to pass through the gut), and decreases carbohydrate absorption rate. Interestingly, insoluble fiber is more consistently shown to reduce the risk of type 2 diabetes than soluble fiber. Insoluble fiber is also associated with increased insulin sensitivity, and decreased gut transit time. In other words, both insoluble and soluble fiber work synergistically to improve blood sugar levels and post prandial glucose response, as well as maintain a healthy bowel.
It is recommended that women consume at least 25 gram/day, and men consume at least 38 grams/day. (R)
Accelerated Gastric Emptying
Accelerated gastric emptying (food moves too fast from the stomach to the small intestine) is associated with reactive hypoglycemia.
Symptoms of hypoglycemia include fatigue, tremors, sweating, nausea, feeling faint, and lightheadedness. When these symptoms occur between one and three hours after eating, it suggests possible reactive hypoglycemia. Reactive hypoglycemia is diagnosed by a one or two hour glucose level ≤3.9 mmol/L or a one or two hour glucose level that is less than fasting glucose after an oral glucose load, or it can be diagnosed with a plasma glucose level <3 mmol/L in the post-prandial period. (R)
Persons with reactive hypoglycemia have been found to respond well to a ‘grazing diet’, which is eating smaller meals more often, instead of eating two or three large meals each day. (R)
However, some people find that the quality as much as the quantity of the meals makes all the difference. Grazing on crackers vs. grazing on nuts and seeds will likely have completely different influences on blood sugar. Also, some find that eating larger meals with lots of fiber and moderate amounts of protein and fat works better, because they are able to “construct” a balanced meal more easily than what a grazing diet would allow.
Low Carb Diets
First, let’s understand what “low carb” actually means.
Defining Carbohydrate Diets
- Very Low Carbohydrate – 21-70 g/day
- Moderately Low Carbohydrate – 30-39.9% of energy
- Moderate Carbohydrate – 40-65% of energy
- High Carbohydrate - >65% of energy
Weight loss is important for controlling blood sugar, and in terms of weight loss, low carbohydrate diets are generally better in the short term compared to higher carbohydrate diets, but after a year or so, weight loss between the two diets are similar. (R)
Some studies are a bit mixed, but it appears that consuming lower amounts of carbohydrates lowers A1c levels, and allows persons with diabetes to rely less on medications for managing blood glucose. However, consistently consuming low amounts of carbohydrate and high amounts of protein may lead to insulin resistance depending on your genetics, which likely occurs as a protective mechanism due to not consuming enough glucose. The “Carnivore Connection” is the idea that during Paleolithic times when sources of dietary carbohydrates were low, insulin resistance provided a mechanism to surviving. The genes were then passed down to us, which might explain why insulin resistance sometimes increases when eating fewer carbohydrates. (R)
Another idea known as the thrifty genotype theory, explains that an increase in insulin resistance is actually due to caloric restriction, rather than carbohydrate restriction. Either way, this is actually very fascinating. (R)
Genes: Individuals who are homozygous for transcription factor 7-like 2 TCT7L2 rs7903146 T-risk allele have been found to respond better to a lower fat (20-25%) higher carbohydrate (60-65%) diet than a higher fat (40-45%) lower carbohydrate (40-45%) diet. (R)
When carbohydrate consumption is restricted, the body will adapt and instead of using glucose as the main energy source, it will instead begin to use fat as an energy source. When carbohydrates are very restricted, the body will enter a state of ketosis. In order to achieve this state of fat oxidation, carbohydrates need to be restricted to somewhere between 20-50 g/day. The body will be able to maintain normal glucose levels through gluconeogenic pathways, by producing glucose from “non-glucose” sources such as protein. The idea behind low carb and ketogenic diets is that since less exogenous carbohydrate is consumed, the body will need to rely less on glucose and therefore less insulin is needed to maintain healthy blood sugar levels.
I’m not particularly fond of the ketogenic diet (very low carbohydrate), but it’s still worth discussing, since we are all different, and someone might find that a ketogenic diet works best for them. Ketogenic diets have been found to lower blood glucose and HbA1c levels significantly (R) (R) (R) and improve insulin sensitivity. (R)
As with a lot of studies, it’s difficult to tell whether improved glycemic control is due to weight loss or if it’s due to dietary changes. If you decide you want to try a ketogenic diet, be sure to do lots of research and work with a qualified individual.
Low carb diets (75g/day or less) have been shown to lower HbA1c levels in person with type 1 diabetes. Persons with type 1 diabetes need to estimate the amount of carbohydrates contained in a meal. If they eat less carbs, there is a better chance of estimating how much is contained in the meal. This means that insulin dosing will be more accurate, and less insulin is needed since less carbohydrates are being eaten. All of this together leads to better blood glucose control and less fluctuations. (R)
Intraabdominal fat is the greatest risk factor for insulin resistance and type 2 diabetes. This factor definitely needs to be considered when understanding the differences between studies comparing the metabolic effects of different macronutrient ratio diets. Here’s a hypothetical example. If people with insulin resistance lose weight on a low carb diet, it’s likely that their insulin resistance will improve. If the same study found that people with insulin resistance did not lose weight on a high carb diet, then their insulin resistance probably didn’t improve. This means that the low fat diet would be considered to improve insulin resistance, but the high carb diet would not.
It’s likely that any diet and lifestyle that reduces intraabdominal fat will improve insulin sensitivity, as long as the diet and lifestyle doesn’t cause other harm, such as increase inflammation significantly. (R)
Exercise and Weight Loss
Moderate exercise (90 min of brisk walking) lowers glucose levels after eating, as well as lowers triglycerides by about 50%. Even light exercise activity lowers glucose levels 2 hours after eating. Being sedentary is definitely not good for your blood sugar, as being sedentary is associated with higher post-prandial blood glucose levels. (R)
Weight loss of 5%-10% or more decreases post-prandial glucose, and reduces the risk of diabetes. (R)
Consuming a low glycemic index meal before exercising is a good idea if you’re trying to burn fat. Doing so will cause your body to “more easily” mobilize and oxidize fatty acids from adipose (fat) tissue during exercise, because less glucose is available. (R) This is definitely beneficial for reducing visceral fat.
Muscle contraction increases the uptake of glucose into cells by increasing GLUT4 transporters. A 2-week exercise program increases GLUT4 by 369% in persons with diabetes. (R) GLUT 4 is a key glucose transporter, and is regulated by both insulin and muscle contraction. During muscle contraction and exercise, more GLUT 4 is translocated to the outside of the cell to help move glucose out of the blood and in to the cell, which lowers blood glucose levels. This means that less insulin is needed to lower blood glucose. Exercise therefore increases glucose tolerance, which lasts for somewhere between 24 and 72 hours, depending on the duration and intensity of the exercise performed. (R)
Persons without diabetes have been found to have increased insulin sensitivity for up to 3 days after a few minutes of sprinting, totaling 7.5 to 20 minutes/week. These people achieved similar insulin sensitivity as people who run at 65% VO2max for 150 minutes/week. (R)
This means that the higher the intensity, the less time is needed to increase insulin sensitivity. Persons with diabetes should always review exercising programs with their doctor, because exercise can actually raise blood glucose levels temporarily, and as insulin sensitivity increases, insulin dosing will likely need to be changed.
Therefore, exercise is very powerful for maintaining healthy blood glucose levels in both persons with and without diabetes, and should be a part of everyone’s lifestyle as long as you are able to safely do so.
Consuming 1-2 tablespoons of vinegar with a meal significantly reduces post-prandial blood sugar by 25%-35%, and keeps you feeling satiated. This is because the acetic acid in vinegar slows gastric emptying. (R)
Tip: make homemade salad dressing with vinegar and olive oil. Eat a salad at least once a day with lunch or dinner.
Nuts are a fantastic food to help lower the glycemic response. When nuts are consumed with high glycemic foods, they lower the blood glucose and insulin spikes. Nuts also contain antioxidants, which provide some protection from oxidative stress associated with post prandial glucose spikes. (R) (R)
Tip: snack on nuts and seeds, add them to salads, oatmeal, etc.
Cinnamon is rich in antioxidants and significantly reduces the blood sugar spike by slowing gastric emptying. (R)
Cinnamon also has been found to increase glucose uptake and GLUT4 expression, and decrease fasting blood glucose and HbA1c. The results are a bit mixed on cinnamon, but it’s definitely worth a shot. (R) (R)
Epigallocatechin gallate (EGCG) is the main compound in green tea that gives it its powerful health benefits. EGCG has the ability to inhibit fat cell growth and increases fat oxidation and energy expenditure, which could help with fat loss and therefore blood sugar issues. (R)
Having 1-2 alcoholic beverages immediately before a meal decreases post-prandial glucose and insulin levels in healthy persons without diabetes. A moderate amount of alcohol improves glucose metabolism for about 12 to 24 hours. (R)
If you are going to drink alcohol, I highly recommend red wine, because it conatins chromium (see below), and other beneficial compounds.
Some believe eggs lead to insulin resistance. Eggs do not appear to have any negative effect on glycemic control and insulin resistance. Randomized trials of persons consuming 2-3 eggs for 6-12 weeks have shown no changes in fasting blood glucose, postprandial glucose, HbA1c, or fasting insulin levels. One study actually found that eggs lowered insulin levels and improved insulin sensitivity. (R)
I suppose anything is possible in the land of nutrition studies. If eggs did cause insulin resistance in someone, it would probably be that the person has an inflammatory reaction to eggs.
Consuming whole grains is a better option in terms of glucose homeostasis than consuming refined grains. Overweight hyperinsulinemic adults who eat whole grains have been found to have 10% lower fasting insulin levels than those who eat refined grains. (R) Basically, refined grains are grains that are stripped of their fiber, antioxidants, and much of their nutrients. This is why refined grains are often fortified or enriched with nutrients, because without the nutrients added back, the refined grains are virtually empty calories. The fiber plays an important role in slowing the rise in glucose after eating.
Simply consume whole grains instead of refined grains.
If you eat bread, go with sprouted grain bread, since it reduces the glycemic response more than white, whole-grain, and sourdough breads. (R)
White rice has a super high glycemic index value of 96, which when eaten alone, induces a high glycemic response. However, when eaten with a normal meal of chicken, vegetables, and oil, the glycemic index of the meal drops to 50. (R)
If you are eating white rice with lots of fibrous foods, moderate amounts of protein and fat, then some white rice shouldn’t be a huge problem if you don’t have diabetes. If you have blood sugar spikes from it, then reduce the amount of white rice you eat in one sitting and/or switch to brown rice.
When saturated fats are replaced with polyunsaturated fats, fasting glucose decreases. Also, when 5% of calories from either carbohydrates or saturated fats are replaced with 5% of calories from either monounsaturated or polyunsaturated fats, HbA1c decreases. Polyunsaturated fats are somewhat demonized, but studies show that they do have the capacity to lower fasting glucose, lower HbA1c, and improve insulin secretion. Monounsaturated fat doesn’t affect fasting glucose much, but does reduce HbA1c compared to carbohydrate or saturated fat.
Therefore, polyunsaturated or monounsaturated fat should be your go to dietary fats. Examples of good sources of healthy fats are nuts, seeds, avocadoes, olives and olive oil, and fish. (R)
Consuming 30% protein, 40% carbohydrate, 30% fat lowers postprandial glucose and decreases HbA1c by 0.5% compared to a diet consisting of 15% protein, 55% carbohydrate, and 30% fat in persons with type 2 diabetes. This study found that increasing protein and lowering carbohydrate helps improve blood glucose control. (R)
Lean protein lowers the spike in blood sugar and increases the insulin response significantly. (R)
Low levels of chromium in animals and humans is associated with diabetes. Chromium is a beneficial nutrient that has been found to help maintain healthy blood glucose, but the results of studies looking at chromium and blood glucose are mixed. Be sure you are consuming enough dietary chromium, since many US adults do not consume enough of it. The mechanism behind chromium’s ability to help manage blood glucose isn’t well understood, but it appears that it potentiates the action of insulin and increases insulin sensitivity. (R)
Adequate Intakes (AIs) for Chromium (mcg/day) (R)
- 0 to 6 months: 0.2 mcg/day
- 7 to 12 months: 5.5 mcg/day
- 1 to 3 years: 11 mcg/day
- 4 to 8 years: 15 mcg/day
- Males age 9 to 13 years: 25 mcg/day
- Females age 9 to 13 years: 21 mcg/day
Adolescents and Adults
- Males age 14 to 50: 35 mcg/day
- Males age 51 and over: 30 mcg/day
- Females age 14 to 18: 24 mcg/day
- Females age 19 to 50: 25 mcg/day
- Females age 51 and older: 20 mcg/day
- Pregnant females age 19 to 50: 30 mcg/day
- Lactating females age 19 to 50: 45 mcg/day
Food Sources of Chromium (R)
- Broccoli, ½ cup – 11 mcg
- Grape Juice, 1 cup – 8 mcg
- English muffin, 1 whole wheat – 4 mcg
- Potatoes, mashed, 1 cup – 3 mcg
- Garlic, dried, 1 teaspoon – 3 mcg
- Basil, dried, 1 tablespoon – 2 mcg
- Beef, 3 ounces – 2 mcg
- Orange juice, 1 cup – 2 mcg
- Turkey breast, 3 ounces – 2 mcg
- Whole wheat bread, 2 slices – 2 mcg
- Red wine, 5 ounces – 1-13 mcg
- Apple, 1 medium – 1 mcg
- Banana, 1 medium – 1 mcg
- Green beans, ½ cup – 1 mcg
Grape and orange juice aren’t exactly the best choices for people with blood sugar issues, but it’s still worth noting that they contain chromium. Vitamin C and niacin increase the absorption of chromium, so it’s a good idea to pair high vitamin C foods with foods high in chromium. Medications that decrease stomach acid decrease the absorption of chromium, they also tend to decrease the absorption of other nutrients as well.
Disrupted sleep and not getting enough sleep is associated with impaired glucose tolerance. (R)
In the 1960s, the average night’s sleep was 8 hours. In 2012, the average was 6.5 hours, which is putting people in a chronic sleep deprivation state. (R)
Maintaining a good circadian rhythm is important for many metabolic functions, including glucose homeostasis. Be sure you’re getting a full healthy nights rest.