Research Supporting Low Carb Diets For Type 2 Diabetes & Other Metabolic Conditions
Researchers have demonstrated sufficient benefits to a low carbohydrate or ketogenic diet in the treatment of metabolic diseases that the American Diabetes Association, in its Standards of Medical Care, acknowledged that low-carbohydrate ketogenic diets are a viable nutrition therapy for type 2 diabetes. They stated “In addition, research indicates that low-carbohydrate eating plans may result in improved glycemia and have the potential to reduce antihyperglycemic medications for individuals with type 2 diabetes.” There are multiple other research studies supporting this guideline. We will share additional supportive research below.
The ADA has also acknowledged that a low or very-low carbohydrate diet has not been shown to increase cardiovascular disease risk factors.
Very low-carbohydrate ketogenic diets, which Revero nutrition therapy is based on, have been shown in an analysis of 42 published studies to improve type 2 diabetes markers compared to nine other types of diets. Findings of this analysis showed that the ketogenic diet intervention resulted in reduced HbA1C, as well as body weight reduction in overweight patients and improvements in blood lipid levels.
Low-carb ketogenic diets have also been shown to improve many other aspects of metabolic health:
A low-carb diet program improves obesity and type 2 diabetes management
A healthcare provider in Australia enrolled patients with obesity and type 2 diabetes on a low-carb diet plan with hands-on coaching and monitoring over several months and showed effective improvement in weight, HgbA1C, blood pressure, lipids and great reduction in medications prescribed.
A low-carb approach leads to major weight loss and type 2 diabetes improvement
This is an 8 year study at Dr. Unwin’s primary care practice in the UK shows how a low carb diet led to significant weight loss and improvement in type 2 diabetes with 20% of the entire practice type 2 diabetes population achieving drug-free remission. It also showed substantial financial savings.
A low-carb diet is superior to a low-fat diet to treat obesity and high triglyceride levels
This is a randomized controlled trial comparing a low-fat calorie-restricted diet with low-carb ketogenic diet. The low-carb group showed better participant retention, greater weight loss and greater decrease in triglyceride levels and increase in HDL levels.
A low-carb diet leads to more weight loss and lower triglyceride level than a low-fat diet
This is a randomized trial showing severely obese subjects with a high prevalence of diabetes or the metabolic syndrome lost more weight during six months on a low-carb diet than on a calorie- and fat-restricted diet, with a relative improvement in insulin sensitivity and triglyceride levels.
A low-carb diet shows sustained improvement in blood pressure and lipid profile
This study by Dr. Unwin in the UK highlights the effect of a low-carb diet over 2 years, showing marked reduction in blood pressure and lipid profile and a 20% reduction in medication use for blood pressure.
A very low-carb diet is superior to the DASH diet for blood pressure, glycemic, and weight control
This is a randomized trial showing that for adults with triple comorbidities (hypertension, prediabetes or type 2 diabetes, and overweight or obesity), the VLC diet resulted in greater improvements in systolic blood pressure, glycemic control, and weight over a 4-month period compared with the DASH diet.
For a portion of the patient population, low-density lipoprotein (LDL) levels will rise, and yet cardiovascular risk will be lower. This is possible because LDL levels comprise a total of different particle sizes, from small dense LDL particles to large buoyant LDL particles. Research evaluating the body of evidence has concluded that small, dense LDL particles are a major, independent risk factor for cardiovascular disease. These small LDL particles continued to define cardiovascular risk even in patients with “normal” LDL levels as well as those undergoing statin therapy. Research has indicated that large buoyant LDL particles do not contribute to cardiovascular disease risk.
Analysis of 38 randomized trials in a published review concluded that carbohydrate restricted diets reduce the abundance of small dense LDL particles while increasing the level of non-atherogenic large buoyant LDL particles. Sometimes the net effect is an increase in total LDL, though with a lower cardiovascular risk due to the predominance of large particle LDL.
Besides, irrespective of LDL cholesterol, type 2 diabetes is one of the biggest risk factors for cardiovascular disease (CVD), and improving diabetes control by lowering HbA1C with a low carbohydrate diet will likely help improve CVD risk. Also, obesity, high triglycerides and hypertension, which are all known independent risk factors for CVD, also have been shown to improve on a low carbohydrate diet, effectively lowering CVD risk (See table above).
Low Carbohydrate Diets and Obesity
Long-term ketogenic diets have been shown to result in reduced body weight, BMI, as well as also reducing triglycerides, blood glucose levels, and LDL cholesterol in obese patients. Compared to low-fat diets for obesity, the ketogenic diet not only result in greater weight loss, but also in a larger reduction in blood triglyceride levels and a larger increase in HDL cholesterol.
There are several mechanisms that have been identified as responsible for this finding. Carbohydrates have been shown to reduce HDL cholesterol while elevating triglyceride levels. This occurs because insulin promotes energy storage, often by increasing fat storage in adipocytes. Carbohydrates are converted into triglycerides, then sent to fat cells for storage. As a ketogenic diet results in less triglycerides formed, and lower insulin levels, the diet helps the body switch modes from lipogenesis to instead mitochondrial biogenesis. This results in increased rates of fat oxidation, which facilitate weight loss.
One additional factor that contributes to weight loss occurs because ketogenic diets suppress the hunger hormone, ghrelin. This ability of a low-carbohydrate high-fat diet to produce satiety at a reduced energy intake is a contributor to the overall anti-obesity effect of the ketogenic diet.
Low Carbohydrate Diets and Hypertension
Sodium and hydration levels are controlled within fairly rigid parameters by the human body, because sodium is so critical to a variety of body functions such as nerve conduction. It has long been proven that insulin resistance results in the kidneys retaining sodium. This sodium retention also results in a corresponding water retention, to prevent an increase in the concentration of sodium. Increased water retention results in increased blood volume, raising blood pressure. While a low-sodium diet does sometimes result in reduced blood pressure, it doesn’t address the root cause, which is elevated insulin levels that result from insulin resistance. When low-carbohydrate diets are tested in hypertensive patients, the result is a significant reduction in blood pressure and a 21.5% simultaneous reduction in hypertension medication use. This is thought to be the result of reduced insulin levels and improved insulin sensitivity, normalizing the sodium retention by the kidneys, which allows release of the retained water and a reduction in blood pressure.
Telehealth Virtual Care has Proven Effective for Type 2 Diabetes
Telehealth came to the forefront during COVID-19 lockdowns, as attempts were made to utilize virtual platforms to maintain communication and compliance with patients with type 2 diabetes. Virtual care for patients with type 2 diabetes in particular was of interest because elevated HbA1C and BMI were found to be predictive of mortality in SARS-CoV2 infection. The situation also provided the opportunity to evaluate how well this care model performed in patients with type 2 diabetes.
The use of telehealth for type 2 diabetes care increased during this period, and improvements in HbA1C and deprescription of some medications has now been documented in research, validating the use of telehealth for management of type 2 diabetes.
Low Carbohydrate Elimination Diets For Autoimmune or Inflammatory Conditions
Elimination diets involve systematically eliminating foods or food ingredients that are suspected of triggering a harmful response. This strategy is often used to help control inflammatory or autoimmune conditions. In some cases those foods can later be slowly reintroduced, but sometimes they must be eliminated for life.
An example of one step in an elimination diet would be a low-FODMAP diet. FODMAP is an acronym for Fermentable Oligosaccharides, Disaccharides Monosaccharides And Polyols. Low FODMAP diets have been found to reduce the symptoms of inflammatory bowel disease.
Another example of an elimination diet is the Autoimmune Protocol Diet (AIP) which involves the elimination of grains, legumes, nightshades, dairy, eggs, coffee, alcohol, nuts/seeds, refined sugars, oils, NSAIDS, and all food additives. This diet has been found to alter the expression of intestinal RNA, modulating immune response to food in patients with autoimmune ulcerative colitis.
The elimination of gluten is also a form of elimination diet. While primarily used as an intervention for celiac disease or non-celiac gluten sensitivity, elimination of gluten also has shown to be helpful with Hashimoto’s thyroiditis. Non-celiac gluten sensitivity (NCGS) has been demonstrated with anti-gliadin antibodies (gliadin is a peptide that gluten breaks down into), with a significant correlation to autoimmune thyroiditis.
Paleolithic, or Paleo diets, which seek to mimic the dietary profiles of human ancestors, have also been used as a form of elimination diet. One application of Paleo diets is for the autoimmune conditions Hashimoto’s thyroiditis and Grave’s disease.
There are also many other food reactions that can be identified via elimination diets, including reactions to carrageenan or food dyes.
These elimination diet strategies can easily be incorporated into a low-carbohydrate diet, providing a way to determine if the condition responds to the elimination strategy.
The effect of the Ketogenic diet on inflammatory arthritis conditions
There is evidence supporting improvement in biomechanical and biochemical markers as insulin resistance improves in these patients leading to improved systemic inflammation and the benefits of fasting in improving rheumatoid arthritis symptoms, partially due to ketones.
A Gluten-free diet improves a subset of psoriasis
This study shows that a gluten-free diet improves psoriasis for patients with positive antibodies to gliadin. Although data remains limited, this shows a connection between diet and certain autoimmune conditions, where an elimination diet might be helpful.
A personalized elimination diet improved IBS and IBD symptoms
This pilot study showed that a digitally delivered personalized elimination diet improved the symptoms and quality of life for patients with IBS and comorbid IBS/IBD. IBD included ulcerative colitis and Crohn’s disease.
A low FODMAP diet improves IBS-like symptoms in IBD patients
This is a prospective study showing that a low FODMAP elimination diet improved IBS-like symptoms in patients with IBD in remissions. The study was not large enough to draw conclusions about active IBD, but adds to the body of knowledge that diet and autoimmune diseases like IBD may be connected.
An elimination diet improves thyroid function in women with obesity and hashimoto’s
This is a study showing that women with obesity and hypothyroidism due to hashimoto’s thyroiditis had better thyroid function when a personalized elimination diet was added to a calorie restriction diet indicating that an elimination diet has additional benefit to simple weight loss in improving thyroid function in women with obesity.
A Paleo diet improves autoimmune thyroid diseases
This is a systematic review study showing that an elimination diet (Paleo or ancestral diet), improves autoimmune thyroid disease by reducing thyroid antibodies and improving thyroid hormone levels.
Type 2 Diabetes, Hemoglobin A1c
1. Study showing reduced A1c https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9408028/
2. Study showing reduced A1c https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2633336/
Obesity and weight loss
3. Significant Weight loss https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9609895/
4. Significant Weight loss https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9962697/
5. Significant Weight loss https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10210464/
6. Reduced triglyceride levels https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6959586/
7. Reduced triglyceride levels https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4351995/
8. Reduced triglyceride levels https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2716748/
9. Reduced blood pressure https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0225348
10. Reduced blood pressure https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6959586/
11. Markedly decreased liver fat in six days https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7132133/
12. Improve mitochondrial function, decrease oxidative stress https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5981249/
13. Lectins can trigger Rheumatoid arthritis https://pubmed.ncbi.nlm.nih.gov/10884708/
14. Lectins are implicated in certain autoimmune diseases https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1115436/
15. Dairy and food dyes may trigger Rheumatoid Arthritis https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1004647/
16. Elimination of gluten, nightshades, and alcohol helped psoriasis https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5453925/
17. Antibodies to gliadin, a metabolite of wheat, as psoriasis biomarkers https://pubmed.ncbi.nlm.nih.gov/31671471/
18. Association between psoriatic arthritis and metabolic syndrome https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8860394/
19. A Gluten-free diet results in decreased expression of tissue transglutaminase and proliferating (Ki67) cells https://pubmed.ncbi.nlm.nih.gov/14690336/
20. Reduced markers of inflammation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4025600/
21. Reduced markers of inflammation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3705319/
22. Reduced markers of inflammation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7923314/
IBS, Ulcerative colitis, and other inflammatory bowel conditions
23. Reduced symptoms of irritable bowel syndrome https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2693479/
24. Reduced medication, gut bacteria changes, immunomodulation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7147823/
25. Reduced medication, gut bacteria changes, immunomodulation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8062677/
26. Reduced medication, gut bacteria changes, immunomodulation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8539934/
27. Increased thyroid hormone https://pubmed.ncbi.nlm.nih.gov/30060266/
28. Increased thyroid hormone https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6315522/
29. Reduced anti-thyroid antibodies Improved thyroid hormone levels https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5435852/
30. Reduced anti-thyroid antibodies Improved thyroid hormone levels https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5897856/