2. The patient has normal glycemic measures (e.g., normal HbA1c, normal fasting blood glucose).
3. Both of the above are maintained for at least one year.
There is strong and consistent evidence that many people who are motivated to kick diabetes can succeed in this task. The initial scientific data came from studies of people who had undergone bariatric surgery. Following surgery, normal glucose metabolism is rapidly restored in the majority of patients. Liver fat declines within days, normalizing fasting blood glucose, and pancreas fat drops within weeks, restoring insulin secretion and beta cell function.
4 , 5
Diabetes reversal is a product of the degree of weight loss over time. People who lose the greatest amount of weight over time experience the highest success rates.
TABLE 2.1. Summary of Consensus Definitions
PARTIAL REMISSION
COMPLETE REMISSION
PROLONGED REMISSION
Hyperglycemia below diagnostic thresholds for diabetes
Normal glycemic measures
At least one year’s duration
At least one year’s duration
Complete remission of at least five years’ duration
No active pharmacologic therapy or ongoing procedures
No active pharmacologic therapy or ongoing procedures
The second line of evidence comes from studies of significant diet and lifestyle changes made by patients with diabetes. Several studies have established the reversal of diabetes using energy (calorie) restriction. Studies using very low-calorie diets mirror the results of bariatric surgery. For example, in 2011, one research team reported that after just one week of energy restriction (600 kcal/day), fasting glucose normalized.
Liver fat diminished, as did liver glucose production.
By eight weeks, insulin response was superior to the nondiabetic controls and pancreatic fat declined significantly.
The authors concluded that normalization of both beta cell function and liver insulin sensitivity was achieved by dietary energy restriction alone.
A 2017 study reported that a twelve-week, low-calorie diet (about 1,000 kcal/day) produced normal blood glucose in 50 percent of the cohort, despite stopping all diabetes medications.
In 2018, the Diabetes Remission Clinical Trial (DIRECT) released results of a clinical trial that randomized patients to a weight-management program using a total diet replacement formula (825, 853 kcal/day) or a control group using best-practice care guidelines.
The formula provided 59 percent carbohydrate, 2 percent fiber, 13 percent fat, and 26 percent protein.
It was used for three to five months, followed by a structured food-reintroduction program.
At twelve months, a weight loss of at least thirty-three pounds (15 kg) was reported in 24 percent of the participants in the intervention group, but no weight loss was shown in participants in the control group.
Diabetes remission was achieved in 46 percent of the intervention-group participants and 4 percent of participants in the control group.
Remission rates increased with weight loss.
■ 0, 11 pounds (0, 5 kg) weight loss = 7 percent remission rate
■ 11, 22 pounds (5, 10 kg) weight loss = 34 percent remission rate
■ 22, 33 pounds (10, 15 kg) weight loss = 57 percent remission rate
■ 33 pounds (15 kg) or greater weight loss = 86 percent remission rate
A more gradual reversal of insulin resistance has also been demonstrated using diets that are less calorically restrictive, along with appropriate lifestyle changes. In such cases, liver and pancreas fat decline more gradually, insulin sensitivity is more slowly restored, and a healthy metabolism is reestablished. A 2012 pilot study of thirteen adults with diabetes reported impressive changes in a number of measurements (see table 2.2 , page 18 ).
Sixty-two percent of participants achieved normal blood glucose levels.
TABLE 2.2. High Nutrient Density (HND) Diet: Lab Changes in Seven Months (Mean)
LAB MEASURE
BASELINE
7 MONTHS ON HND DIET
HbAlc
8.2%
5.8%
Body weight
217 lbs (98.6 kg)
173 lbs (78.6 kg)
Blood pressure
148/87
121/74
Triglycerides
171 mg/dL (1.9 mmol/L)
103 mg/dL (1.2 mmol/L)
LDL cholesterol
135 mg/dL (3.5 mmol/L)
113 mg/dL (2.9 mmol/L)
HDL cholesterol
48.3 mg/dL (1.3 mmol/L)
54.6 mg/dL (1.4 mmol/L)
A diet that was plant-rich with a high nutrient density (HND) was used in this study, incorporating foods with significant micronutrient content per calorie.
Greens and other nonstarchy vegetables, such as onions, mushrooms, eggplants, peppers, tomatoes, and cauliflower, were emphasized and consumed in unlimited amounts.
Foods with a high glycemic index were reduced, while carbohydrate-rich, high-fiber foods with a low glycemic index, such as beans, peas, squash, and intact grains, were included.
Nuts and seeds were the primary sources of fat.
Animal products were limited to no more than 10 percent of calories.
The dietary protocol was as follows
■ At least one large green salad a day, with the inclusion of a salad dressing derived from nuts or seeds
■ One bowl of vegetable-bean soup daily
■ One to two ounces (30, 60 g) of raw seeds and nuts daily (usually in a salad dressing)
■ Approximately three or four servings of fresh fruits per day
■ One large serving of steamed or stewed greens, with mushrooms, onions, and other low-starch veggies
■ Only one serving daily (½ cup/125 ml) of starchy foods exclusive of legumes, such as squash, steel-cut oats, or brown or wild rice
■ Exclusion of white flour, sweets, and oils
■ Animal products, if used, limited to not more than 12 ounces (340 g) per week
We can expect to see more studies using various plant-based diets in the near future. One research group (E4 Diabetes Solutions) achieved normalization of HbA1c in 67 percent of their participants using a totally plant-based diet, although this is yet unpublished.
There are multiple case reports of complete remission in individuals who make the necessary diet and lifestyle changes. Each individual who has been diagnosed with diabetes but no longer meets the criteria for this diagnosis sends a powerful message to health-care providers and diabetes sufferers.
There are two main camps claiming success with diabetes reversal: the plant-based camp and the low-carb camp. Let’s examine the research that speaks to each of these diet therapies.
THE PLANT-BASED CAMP
B etween 1976 and 1991, a pioneering research team headed by James W. Anderson, MD, published numerous studies demonstrating that high-fiber, high-carbohydrate, plant-based diets are beneficial for people with diabetes.
11 , 12 , 13 , 14 , 15 , 16 , 17
His team compared participants consuming a plant-based, high-carbohydrate, high-fiber (HCF) diet (carbohydrates at 70 percent of calories and fiber at 35, 40 g per 1,000 calories) with those consuming the conventional diabetes diet (43 percent carbohydrate) recommended by the American Diabetes Association (ADA).
Participants on the HCF diet had consistently more favorable plasma glucose values, glucose tolerance, insulin sensitivity, and blood lipids than those on the ADA diet.
In addition, the majority of patients on the HCF diet were able to discontinue or dramatically reduce their oral medications and insulin.
Even when participants shifted to a maintenance diet providing fewer carbohydrates (55, 60 percent of calories) and less fiber (25 g per 1,000 calories), most were able to sustain favorable changes in lab measurements after an average of fifteen months, while staying off medications and insulin.
These studies suggest that diets rich in fiber and unprocessed carbohydrates result in lower insulin requirements than higher-fat conventional diabetes diets.
The practical implications of these findings are impressive.
1. A diet providing 70 percent of energy from carbohydrate and containing 35, 40 g of fiber per 1,000 calories can rapidly reduce the plasma glucose level and the requirement for insulin or oral hypoglycemic agents in patients with diabetes. It can also lower serum cholesterol and elevated triglyceride levels.
2. Improvements can be maintained long term in patients following a modified high-carbohydrate, high-fiber diet providing 55, 60 percent of energy from carbohydrate, 15, 20 percent from protein, and 20, 30 percent from fat, with 25 g of plant fiber per 1,000 calories.
From 1992 to 1995, Dr. Anderson’s team released results of another series of studies that examined the impact of very low-calorie diets (VLCD) in obese individuals with diabetes. Diets providing 400, 800 calories per day resulted in an average weight loss of forty-six pounds (21 kg) in sixteen weeks. In addition, significant reductions in blood glucose, HbA1c, total cholesterol, LDL cholesterol, triglycerides, and blood pressure were reported.
18 , 19 , 20
Further, between 1999 and 2013, the team reported favorable changes in glucose and lipid levels with the intake of specific plant foods, including beans, psyllium, whole grains, and raisins,
21 , 22 , 23 , 24 , 25
and in renal function with the intake of soy protein.
26 , 27
David Jenkins, MD, the architect of the glycemic index (see page 94 ), or GI, coauthored numerous articles demonstrating favorable metabolic consequences of consuming plant-based diets or specific plant-based foods, such as whole grains, nuts, and legumes.
28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37
In 2018, his team released a systematic review and meta-analysis of nine randomized controlled trials assessing the effect of vegetarian diets on individuals with diabetes. Specifically, researchers assessed the risk of developing heart disease or stroke and changes in glycemic control. Vegetarian diets significantly reduced HbA1c, fasting glucose, body weight, waist circumference, LDL cholesterol, and non-HDL cholesterol.
Neal Barnard, MD, and his team at the Physicians Committee for Responsible Medicine (PCRM) published the results of several studies comparing the effects of 100 percent plant-based (vegan) diets versus conventional American Diabetes Association (ADA) diets for the treatment of diabetes. In the initial pilot study, eleven participants were randomized to a low-fat vegan diet or a low-fat conventional diet.
Participants who received the vegan diet had a 28 percent reduction in fasting glucose compared to a 12 percent reduction in those consuming the conventional ADA diet. In the vegan group, oral diabetes medications were discontinued in one participant and reduced in three participants, while no changes in medications were made in the ADA diet group. The participants in the vegan group also experienced significantly greater drops in body weight.
In 2006, Barnard’s team published the results of a larger twenty-two-week randomized clinical trial (RCT) comparing ninety-nine participants with diabetes who were assigned a low-fat vegan diet with those assigned a control diet that met the ADA guidelines.
In the vegan group, 43 percent of the participants were able to reduce diabetes medications compared to 26 percent in the ADA group.
Body weight fell by 14.3 pounds (6.5 kg) in the vegan group and 6.8 pounds (3.1 kg) in the ADA group.
HbA1c was cut by 0.96 percentage point in the vegan group and 0.56 percentage point in the ADA group.
When data excluded those who changed medications, HbA1c dropped 1.23 percentage points in the vegan group and 0.38 percentage point in the ADA group.
Among those who did not change lipid-lowering medications, LDL cholesterol was down 21.2 percent in the vegan group and 10.7 percent in the ADA group.
In 2009, Barnard’s group published seventy-four-week results in this cohort.