Diabetes

Vegan diets can turn type 2 diabetes around

By WhyStopHarmingAnimals.com

For people who already have type 2 diabetes, the question is whether changing the food can bring blood sugar back down. Randomized trials of vegan and plant-based diets show that it can: medication gets cut[1], HbA1c falls further than on the diets diabetes associations recommend[1][4], and some people drop below the line that defines the disease[7].

Vegan against the official diabetes diet

In a 22-week randomized trial published in Diabetes Care in 2006, people with type 2 diabetes were assigned either a low-fat vegan diet or the diet recommended by the American Diabetes Association[1]. 43% of the vegan group cut their diabetes medication[1], against 26% on the ADA diet[1]. Among people whose drugs stayed the same, which lets the diet's effect show on its own, HbA1c (a measure of average blood sugar over about three months) fell 1.23 points on the vegan diet[1] and 0.38 on the ADA diet[1]. Weight fell 6.5 kg[1] against 3.1 kg[1].

The same trial ran on to 74 weeks (American Journal of Clinical Nutrition, 2009). Before any medication changes, HbA1c had fallen 0.40[2] on the vegan diet and 0.01 on the conventional one[2], with bigger drops in total and LDL cholesterol as well[2]. By then the difference in weight loss between the groups was no longer significant[2], which suggests the blood sugar advantage came from more than weight.

What the pooled trials show

Six controlled trials with 255 people[3], pooled in Cardiovascular Diagnosis and Therapy in 2014, found that vegetarian diets lowered HbA1c by 0.39 percentage points[3] compared with the diets they were tested against. Fasting glucose moved the same way, though not significantly[3].

A 2018 review of 11 controlled trials and 433 people[4] (BMJ Open Diabetes Research & Care) found that plant-based diets did better than the official diabetes-association guidelines and other comparison diets on HbA1c, weight and cholesterol[4]. They also did better on depression, quality of life and general wellbeing[4], so the people eating this way weren't just putting up with it[4]. A 2022 pool of 11 trials lasting 12 weeks or more, in people with overweight or type 2 diabetes, found vegan diets cut HbA1c by 0.18 points[5] and body weight by 4.1 kg[5].

Even a narrower change helps[6]. Across randomized trials in people with diabetes, replacing sources of animal protein with plant protein modestly improved HbA1c, fasting glucose and fasting insulin (Nutrients, 2015)[6]. The authors called for longer and larger trials[6].

Below the cut-off

The BROAD study, a randomized trial run in the community, put people with obesity, ischaemic heart disease or type 2 diabetes on a whole-food plant-based diet with no calorie counting[7]. At six months they were about 12 kg lighter[7], their BMI and cholesterol had improved, and HbA1c was down[7]. Two people with diabetes no longer met the diagnostic cut-off[7]. Two is a small count, and it shows what the diet can do for some people rather than how often it happens.

The approach also works outside a clinic. At ten corporate sites, employees randomized to 18 weeks of a low-fat vegan diet with no calorie limits lost 2.9 kg while controls held steady[8], and those with diabetes lowered HbA1c by 0.6 points[8] (European Journal of Clinical Nutrition, 2013).

Because blood sugar can fall quickly on these diets, anyone taking diabetes medication should make the change with their doctor so doses can be adjusted.

Type 1 diabetes

Type 1 is an autoimmune disease, and no diet cures it. Diet still changes how much insulin it takes to manage[9][10]. In a 12-week randomized trial of adults with type 1 diabetes, those on a low-fat vegan diet needed less insulin and became more insulin-sensitive[9], while a portion-controlled group did not change (Clinical Diabetes, 2024)[9]. Daily insulin fell 28%[10] and insulin costs 27%[10] in the vegan group, with no rise in hypo- or hyperglycemia (BMC Nutrition, 2025)[10].

Cow's milk shows up on the other side, in who develops type 1 in the first place[11][12]. A meta-analysis of 96 studies found that children drinking 2–3+ glasses of cow's milk a day had 1.8 times the risk of type 1 diabetes[11], and introducing cow's milk later came with lower risk (EBioMedicine, 2021)[11]. In DAISY, which followed 1,835 children from infancy[12], more cow's milk protein came with more islet autoimmunity and faster progression to type 1[12]. These are associations and don't prove that milk causes the disease, but children have no need for cow's milk, and these findings give families one more reason to leave it out.