Is a low carb diet good for diabetes?
Based on a systematic review and meta-analysis of high quality studies on the association between specific food groups and disease, the foods that are eaten on a low carb diet were found to INCREASE your risk for diabetes, while the foods eaten on a high carbohydrate diet were found to DECREASE your risk for diabetes. Studies that had a high risk of bias or did not adjust for confounding factors like physical activity, smoking, level of education, ethnicity, gender, calorie intake, and BMI were not included in the meta-analysis. Therefore, the findings of the meta-analysis are likely to be causal, rather than mere associations.
Thirteen studies with a total of 29,633 cases of type 2 diabetes showed a clear benefit to eating whole grains. In fact, eating just 2 oz of whole grains per day was linked to a 25% decreased risk of developing type 2 diabetes. Observational studies have found that people who eat whole grains have a lower body fat percentage and reduced fasting blood glucose and insulin concentrations. Whole grains are also a great source of soluble fiber, resistant starch, magnesium, zinc, selenium, potassium, phytic acid, and other phytonutrients that may each independently reduce diabetes risk.
There was evidence of a dose-response benefit to eating vegetables, meaning the risk of developing type 2 diabetes decreased as vegetable intake increased. In fact, just 10 ounces of vegetables daily prevent diabetes risk by 9%. Although no increased benefit was found for consuming more vegetables than this, it’s likely that participants in the studies just weren’t eating enough veggies for this effect to be observed.
Now what may come as a surprise to you is that eating fruit was also associated with a REDUCED risk of developing type 2 diabetes. Fruit contains a high amount of natural sugars, including fructose, which many people blame for causing diabetes. However, based on all the scientific evidence, enjoying sugar as nature intended (in the form of whole fruits) can actually prevent diabetes. Fifteen studies with a total of 70, 968 cases of type 2 diabetes, found that as little as one serving of fruit per day could reduce diabetes risk by 10%. Eating fruit can also result in a reduced body fat percentage.
A total of 21 studies with 44, 474 cases of type 2 diabetes were included in the meta-analysis on dairy and diabetes risk. A significant inverse relationship was found, meaning that more dairy consumption was associated with reduced incidence of type 2 diabetes. This benefit was only observed for low-fat dairy products (like low fat yogurt and cottage cheese) and not high-fat dairy products (like ice cream and cheese). Two-and-a-half cups of dairy per day was associated with a 6% reduced risk of developing type 2 diabetes. Eating fermented dairy products (kefir, yogurt, and cottage cheese) is consistently associated with lower body weight and reduced waist size, possibly by modulating the microbiome and increasing beneficial bacteria in the gut.
There were 6 categories of foods that were associated with an INCREASED risk of developing type 2 diabetes: refined grains, sugar sweetened beverages, eggs, fish, red meat, and processed meat.
Eating seven ounces of refined grains (foods made from flour, breakfast cereals, breads, etc.) per day was associated with an INCREASED risk of developing type 2 diabetes by 14%. Failing to differentiate between refined grains and whole grains in a study could lead to the conclusion that all forms of grains are unhealthy when in fact refined grains have a different effect on the body than grains that are whole (intact, not milled into a flour).
Regarding sugar sweetened beverages, most people know these can lead to type 2 diabetes. However, what many people don’t know is that just one cup of sugar sweetened beverages per day can substantially increase risk. One can of soda contains 12 oz of beverage, which is 1.5 cups. Bottled soda is usually 20 oz, or 2.5 cups! Once again, it’s important to note that studies that lump the effects of consuming sugars from soda pop with the effects of eating sugars contained in whole fruits could lead to the misleading conclusion that all forms of sugar are unhealthy. Extracting sugar from whole foods and then adding it to food and beverages clearly produces a different effect on the body.
Eating eggs was strongly linked with an increased risk of developing type 2 diabetes in 13 studies consisting of 17, 629 cases of type 2 diabetes. Eating just 1 egg per day was enough to increase risk by 13%! One of the reasons why eggs increase your risk of developing diabetes (as well as other diseases such as heart disease and cancer) is because it contains a substance called trimethylamine-N-oxide (a compound also found in high concentrations in beef liver and chicken liver).
Data from 16 studies showed a strong correlation between fish eating and INCREASED risk of developing type 2 diabetes among American study participants. This increased risk may have been observed because fish is often contaminated with mercury and other environmental contaminants (such as BPA) that can increase diabetes risk.
Non-processed red meat was also strongly linked with an increased risk of developing type 2 diabetes. In fact, there was a dose-response relationship meaning that each additional 3 oz of red meat further increased risk of developing type 2 diabetes. Keep in mind that factors such as smoking, physical activity, education level, and BMI were accounted for when assessing the data! High intake of heme iron (the kind of iron found in red meat) and increased body iron storage are both consistently associated with increased risk of diabetes.
Processed meats of all kinds were also strongly associated with type 2 diabetes risk. Less than 2 oz of processed meat per day was associated with an increase in diabetes risk by 30%! Even though processed meats are devoid of any carbohydrates, eating processed meats results in higher fasting blood glucose and insulin concentrations regardless of genetics.
Based on the calculations of the researchers involved in this meta-analysis, if on a daily basis you were to eat 6 oz of red meat, 3 ounces of processed meat, 2 cans of soda pop, and one egg per day, you would triple your risk of developing type 2 diabetes. On the other hand, if you were to completely eliminate those foods and instead eat at least 2 ounces of whole grains, 8 ounces of fruits, 8 ounces of veggies, and 2.5 cups of low fat dairy on a daily basis, you would reduce your risk of developing type 2 diabetes by 80%.
Consuming a plant-based diet has also been consistently associated with reduced incidence of type 2 diabetes and all-cause mortality (early death from any cause). In a study of 41,387 Seventh Day Adventists who all live a similar lifestyle but have different dietary patterns, only 0.54% of those on a 100% plant-based diet developed diabetes. The lacto-ovo vegetarians (people who ate dairy and eggs, but no meat, poultry, or fish) had roughly double the rate of diabetes, and the omnivores had roughly quadruple the rate of diabetes.
Now at this point you may be wondering, “What if I already have diabetes? shouldn’t I eat a low carb diet?”
Well, it turns out that the type of diet that prevents type 2 diabetes can also reverse it. A high carbohydrate, whole food plant-based diet has been repeatedly shown to reverse type 2 diabetes in randomized, controlled clinical trials. In one study that compared the benefits of a high carbohydrate, 100% plant-based diet with the “balanced diet” approach recommended by the American Diabetes Association, HbA1c fell 1.23 points in the plant-based group and only 0.38 points in the ADA group. When a high carbohydrate, plant based diet has been tested against a low carbohydrate, high protein diet for the treatment of type 2 diabetes, both groups lost similar amounts of weight but only the high carbohydrate group decreased their HbA1c, decreased their fasting blood glucose, and improved their insulin sensitivity.