Diet & Nutrition Inspiring People

By Cliff Harvey, Phd

According to the American Diabetic Association, diabetes affects over 10% of Americans while nearly 1/3 have metabolic syndrome or pre-diabetes. Many more people suffer from pre-clinical poor blood sugar control characterized by peaks and troughs of blood sugar, energy crashes, and poor cognition. A healthy diet and lifestyle are key factors in preventing and treating type 2 diabetes (acquired diabetes) and metabolic syndrome. (In this article, I will refer to type 2 diabetes simply as diabetes. Type 1 diabetes is a genetic, auto-immune condition and is not covered in this article).

Prevention of diabetes

Many diets including the Mediterranean diet,1-4  and vegan and vegetarian diets5 have been demonstrated to reduce the risk of developing diabetes. Low-carbohydrate diets also have a significant impact on blood sugar levels and control,6 and they also consistently improve risk factors associated with heart disease and diabetes such as triglycerides and HDL cholesterol, more than higher-carbohydrate diets.7

Overall, any diet that is nutrient-dense and based on mostly unrefined foods is likely to be effective for reducing the risk of diabetes.

Treating metabolic syndrome and diabetes

Low-carbohydrate diets are more effective than other diets for the treatment and management of diabetes. They result in an approximately 150% greater reduction in average glucose levels when compared to higher carbohydrate diets.8 Very low carbohydrate diets (i.e. ketogenic diets) are also effective for diabetes treatment. In one 24-week trial, a ketogenic diet resulted in a 3-fold improvement in blood sugar levels and a 60% increase in weight-loss compared to a calorie-restricted low-glycemic diet.9 Similar results have been observed in out-patient trials,10, 11 and in other controlled trials.12, 13 In another controlled trial over 36-weeks, participants in a ketogenic diet trial experienced a nearly 3-fold greater reduction in blood sugar and had a nearly 4-fold greater loss of weight and a nearly 10-fold greater reduction in triglycerides compared to those following a ‘best-practice’ low-fat diet.14

While many diets based on unrefined foods can help to treat diabetes, low-carbohydrate diets appear to be most effective.

Do any particular foods help to reduce blood sugar?

Having healthy blood sugar levels overall mostly results from a healthy, nutrient-dense diet (based on mostly unrefined foods), exercise, getting enough sleep, having good gut health, and having good approaches to stress-management.

Specifically, some foods might help to reduce blood sugar levels, especially in people with metabolic disorder and diabetes. These might include herbs and spices such as fenugreek and turmeric,15 ginseng,16 and cinnamon.17


Increased dietary protein is often suggested as a way to improve blood sugar control. Even though the body can use amino acids from protein to produce glucose, higher-protein meals don’t spike blood sugar levels after a meal,18 and diets higher in protein help to reduce average blood sugar levels.

In a 5-week study comparing a lower to higher protein diet, increasing protein from 15% to 30% of calories resulted in improved blood glucose control and a >40% reduction in average glucose levels along with improvements in triglycerides.18

Increasing protein in the diet has a range of other health benefits, including improved muscle-to-fat ratio,19-22 reduced bone loss and improved strength (especially as we age),19, 20, 23, 24 and improved cardiovascular health.25, 26 And while in the United States, the average intake of protein is higher than the recommended daily allowance,27, 28  it is well below the recommended levels for optimizing health and performance. Analysis of United States’ eating patterns has caused experts to suggest that people should focus on eating enough protein and not reduce their protein intake.29


Interestingly, research has also shown that people can have quite different blood sugar responses to different foods. In a 2015 study by Zeevi and colleagues, the researchers demonstrated that people could have vastly different blood sugar responses, even to the same foods. Some foods (like beef, quinoa salad and salmon) had almost universally ‘good’ blood sugar responses, while others like pita, chocolate chip cookies, wholemeal bread, sushi, and pasta resulted in higher blood sugar. However, some foods, like chicken livers, potatoes, schnitzel, chicken breast, noodles, hummus, and pizza varied drastically for blood sugar responses between individuals.

The researchers also looked into why there are variations between people. Average blood glucose over time (measured by glycated haemoglobin), body mass index, blood pressure, and the liver enzyme alanine aminotransferase were all associated with higher post-meal blood sugar responses. These are also markers for metabolic syndrome and pre-diabetes. Higher blood sugar levels after meals were also associated with increased inflammation. Microbiome differences were also observed to have an association with blood sugar control, and so, this supports the role of gut-health in blood sugar control.30

Individual responses can vary between individuals. Those with metabolic syndrome are likely to have higher blood sugar responses and to respond negatively to more foods. Gut health also plays an important role. Herbs, spices, and other nutrient-dense foods might help to control blood sugar, and protein is a critical component of a healthy diet for blood sugar control.


While nutrient-dense diets of many types (ones that focus on unrefined whole foods) are effective for reducing diabetes risk overall, for the treatment and management of diabetes lower-carbohydrate diets might be most effective. However, any diet that is based on natural, mostly whole, unrefined foods will be beneficial and so, a healthy diet you can stick to for the long-term (like a whole-food plant-based, Mediterranean, Paleo, low-carb, or keto diet) is going to be the best diet for you. This type of diet will also help to improve gut-health, a known factor in blood sugar control. Other factors of a healthy lifestyle should also be considered for blood sugar control, including:

  • Exercise (including both resistance and aerobic exercise)
  • Reducing stress
  • And getting enough quality sleep



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  2. Schwingshackl L, Missbach B, König J, Hoffmann G. Adherence to a Mediterranean diet and risk of diabetes: a systematic review and meta-analysis. Public Health Nutrition. 2015;18(7):1292-9.
  3. Esposito K, Maiorino MI, Bellastella G, Chiodini P, Panagiotakos D, Giugliano D. A journey into a Mediterranean diet and type 2 diabetes: a systematic review with meta-analyses. BMJ open. 2015;5(8).
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  7. Gardner CD, Trepanowski JF, Del Gobbo LC, Hauser ME, Rigdon J, Ionnidis JPA, et al. Effect of low-fat vs low-carbohydrate diet on 12-month weight loss in overweight adults and the association with genotype pattern or insulin secretion: The DIETFITS randomized clinical trial. JAMA. 2018;319(7):667-79.
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  14. Saslow LR, Mason AE, Kim S, Goldman V, Ploutz-Snyder R, Bayandorian H, et al. An Online Intervention Comparing a Very Low-Carbohydrate Ketogenic Diet and Lifestyle Recommendations Versus a Plate Method Diet in Overweight Individuals With Type 2 Diabetes: A Randomized Controlled Trial. Journal of Medical Internet Research. 2017;19(2):e36.
  15. Chavda BP, Sharma A. Efficacy of Combination of Fenugreek, Amla and Turmeric Powder to Reduce Blood Glucose Level among Diabetics-Literature Review. International Journal of Nursing Care. 2017;5(1):55-9.
  16. Reay JL, Kennedy DO, Scholey AB. Single doses of Panax ginseng (G115) reduce blood glucose levels and improve cognitive performance during sustained mental activity. Journal of Psychopharmacology. 2005;19(4):357-65.
  17. Kirkham S, Akilen R, Sharma S, Tsiami A. The potential of cinnamon to reduce blood glucose levels in patients with type 2 diabetes and insulin resistance. Diabetes, Obesity and Metabolism. 2009;11(12):1100-13.
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