Eating almonds before every meal may result in prediabetes remission Original paper

In this randomized controlled trial in participants with prediabetes, eating almonds before each meal had beneficial effects on glycemic control, body composition, and blood lipids. There was also tentative evidence the intervention led some participants to achieve remission of their prediabetes.

The effects of eating 20 grams of almonds 30 minutes before every major meal in people with prediabetes.

The outcomes assessed included 2-hour postprandial glucose following an oral glucose tolerance test (OGTT), fasting glucose, post-meal glucose, fasting insulin, HOMA-IR (a marker of insulin resistance), HbA1c, body composition, blood lipids, and the inflammatory markers C-reactive protein and TNF-α.

A total of 66 participants (average age of 42) with prediabetes.

Prediabetes was based on a 2-hour post-OGTT of 140–199 mg/dL. Thirty participants also had fasting blood glucose (FBG) levels of 100–125 mg/dL, whereas the remaining 36 had FBG levels of less than 100 mg/dL.

Participants were randomly assigned to consume 20 grams of raw, unsalted almonds (roughly one handful) 30 minutes before breakfast, lunch, and dinner (intervention group) or receive usual care (control group) for 3 months. The almonds provided an estimated 393 calories, 13 grams of protein, 35 grams of fat, and 6 grams of carbohydrates per day.

Both groups were advised to follow a diet rich in vegetables and fruits, select whole grains, select fat-free or low-fat dairy products, limit foods containing partially hydrogenated vegetable oils, and curtail their consumption of sugar-sweetened beverages.

Compared to the control group, the almond group experienced reductions (improvements) in fasting glucose (–6.1 mg/dL), 2-hour post-OGTT glucose (–25.8 mg/dL), postlunch and postdinner glucose, HbA1c (–0.4%), and HOMA-IR. These changes corresponded with a higher number of participants in the almond group achieving normal (i.e., not indicative of prediabetes or diabetes) glucose tolerance (23 vs. 7), fasting glucose (10 vs. 4), and HbA1c (9 vs. 1).

Percentage of participants achieving normal glucose tolerance*

*2-hour post-OGTT glucose level <140 mg/dL.

The almond group experienced reductions in body weight (–3.1 kg), waist circumference (–3.0 cm), body fat percentage (–1.7%), and BMI (–1.2) compared to the control group.

In terms of blood lipids, the almonds group experienced reductions in total cholesterol (–14 mg/dL), LDL-C (–11.8 mg/dL), and VLDL-C (–5.1 mg/dL) compared to the control group.

This trial found impressive improvements in glycemic control, among other benefits, when people with prediabetes ate raw, unsalted almonds 30 minutes before breakfast, lunch, and dinner. Especially noteworthy was the finding that 76.7% of participants eating almonds before each meal achieved normal glucose tolerance at the end of the trial, compared to 23.3% in the control group.

These findings can probably be explained in large part by the weight loss observed in the almond group, itself possibly a result of almond-induced satiety (an effect reported in this trial, as well as several others^[1][2][3]) leading to reductions in food intake at subsequent meals.

Compelling evidence suggests weight loss — to the extent that it corresponds with loss of fat in places like the liver and pancreas — can normalize the insulin resistance characteristic of prediabetes and type 2 diabetes.^[4] In support of this, a review of 17 clinical trials found that weight loss seems to be the primary modifiable determinant of whether a diet can induce type 2 diabetes remission.^[5] Notably, participants in the almond group lost an average 4.7% of their body weight, arguably a clinically important amount of weight loss.

The investigators in the summarized trial used terminology to suggest the almond intervention reversed or induced remission of prediabetes in some participants. And although this might be the case, it’s actually difficult to say for sure, because investigators chose not to report or compare how many total participants in each group were no longer prediabetic according to a commonly accepted definition of prediabetes remission, i.e., a fasting glucose level of less than 100 mg/dL and a 2-hour glucose during OGTT of less than 140 mg/dL.

There are a few other diet and lifestyle interventions that have evidence to support their ability to induce remission of prediabetes, prevent progression to diabetes, or both:

• High-protein diet: A 6-month randomized controlled trial assigned participants with prediabetes to follow a hypocaloric diet that was high protein (HP, 30% of calories from protein) or moderate protein (MP, 15% protein), with the difference made up by carbohydrates. By the end of the trial, 100% of participants assigned to the higher protein diet achieved prediabetes remission, compared to 33.3% with the moderate protein diet.^[6] Interestingly, both groups lost similar amounts of body weight (HP: –9.8%, MP: –11.3%) and body fat (HP: –2.49%, MP: –3.55%) during the trial.

• Reduced calorie, low-fat diet and exercise: In the Diabetes Prevention Trial, participants with prediabetes assigned to follow a calorie-restricted, low-fat diet with regular exercise were twice as likely to achieve prediabetes remission over the course of 3 years compared to a control group.^[7] It was also found that the intervention reduced the relative risk of developing type 2 diabetes by 58%.^[8] These benefits appeared to be due at least in part to the intervention causing weight loss.

• Vitamin D: In a meta-analysis of 3 randomized controlled trials, 14.4% of participants with prediabetes achieved remission of prediabetes when supplementing with vitamin D, compared to 11.1% given a placebo.^[9] It was also found that fewer participants given vitamin D developed type 2 diabetes (22.3% versus 25%).

• Exercise: One 2-year randomized controlled trial in people with prediabetes found that getting regular aerobic exercise, resistance exercise, or a mix of both decreased the relative risk of developing type 2 diabetes by 72%, 65%, and 74%, respectively, compared to no exercise.^[10] In addition, average fasting glucose levels and glucose tolerance reached normal levels in all exercise groups, although exactly how many participants actually achieved prediabetes remission was not reported.

• Curcumin: Although not shown to induce remission of prediabetes, one 9-month clinical trial in people with prediabetes found that fewer participants taking curcumin progressed to type 2 diabetes compared to a placebo (0% vs. 16.4%).^[11]