Have you heard of Michael Pollan, an author, journalist, and professor of journalism at the University of California, Berkeley? Several years ago he wrote a book entitled In Defense of Food: An Eater’s Manifesto. One of the “rules” in his book is startlingly simple yet powerful at the same time: “Eat food. Not too much. Mostly plants.” It’s easy to get caught up in food for many reasons: because managing a chronic disease such as diabetes, trying to lose weight, aiming to stave off the effects of aging, battling food allergies… the list goes on. Despite the many challenges that we face with choosing our foods every day, the fact is that most of us could be better off if we heeded Mr. Pollan’s advice to eat more plants.
Pollan’s book also got me thinking a little more about vegetarian diets. In some ways, they seem to have taken a back seat lately to the animal protein–laden way of eating that many Americans follow. High-protein, low-carbohydrate diets remain popular, especially among people with diabetes, in part, because these diets can help to manage blood glucose. But a vegetarian way of eating has resurfaced as of late. This week and next, I’ll mention three studies that restore the place of plant-based diets on the dinner table.
Vegan Diet Helps Type 2 Diabetes
OK, this study is several years old now, but it bears mentioning. A 22-week study published in the journal Diabetes Care in 2006 compared the effects of a low-fat vegan diet (vegan means that no animal products, including meat, poultry, fish, eggs, and dairy are consumed) with a more traditional “ADA” diet in 99 people with Type 2 diabetes. Half of the participants followed the vegan diet, which provided 75% of calories from carbohydrate, 15% from protein, and 10% from fat. They were instructed to avoid animal foods and added fats, but had no restrictions on portions or calories.
The other half of the participants was asked to follow a more traditional eating plan with 60% to 70% of calories from carbohydrate and monounsaturated fat, such as olive oil; less than 7% of calories from saturated fat; and 15% to 20% of calories from protein. If they were overweight, they were also asked to cut calories by 500–1,000 per day. Neither group was provided with food but they were given help from a dietitian.
Results: Improvements in glucose and lipid levels occurred in both groups. But the vegan group surpassed the ADA group in several ways:
- 43% of the vegan group decreased diabetes medicine versus 26% of the ADA group.
- A1C dropped 0.96% in the vegan group versus 0.56% in the ADA group.
- Average weight loss in the vegans was 14 pounds compared with less than 7 pounds in the ADA group.
- LDL cholesterol dropped an average of 21% in the vegan group versus 11% in the ADA group.
- Urine albumin (protein) levels (a marker of kidney function) dropped 15.9 points in the vegans versus 10.9 in the ADA group.
Conclusions: Both groups enjoyed improvements, likely in part because they were making better food choices. But the vegan group did better. And another pleasant finding: The vegan group wasn’t limited in their calories, carbohydrates, or portions, which may have made this eating plan a little easier to swallow.
Eco-Atkins Diet Helps with Weight Loss and Improved Lipids
Here’s a more recent study, published in the Archives of Internal Medicine in 2009. This study didn’t involve people who had diabetes. Forty-seven overweight men and women with high blood lipids were assigned to either a low-carbohydrate or high-carbohydrate diet for one month. The low-carbohydrate diet provided 130 grams of carbohydrate (the minimum amount of carbohydrate that’s recommended), or 26% of calories from carbohydrate, along with 31% from protein and 43% from fat. However, the low-carbohydrate diet was completely vegetarian. Protein came from gluten, soy and nuts. The high-carbohydrate diet was low in fat and also lacto-ovo vegetarian (milk and eggs were allowed), with 58% of calories from carbohydrate, 16% from protein, and 25% from fat. Both diets provided just 60% of calorie needs, designed to promote weight loss.
- Weight loss was about the same in both groups (about 9 pounds).
- Both diets promoted satiety (fullness).
- LDL dropped 20% in the low-carbohydrate group versus 12% in the high-carbohydrate group.
- Triglycerides dropped 29% in the low-carbohydrate group versus 18% in the high-carbohydrate group.
- Systolic (the top number) blood pressure dropped 2.2 points in the low-carbohydrate group versus 1.7 points in the high-carbohydrate group.
Conclusions: Traditional high protein diets, such as Atkins, are typically centered on eating fairly large amounts of animal protein. While these diets do result in weight loss and improved glucose, they often boost LDL (“bad”) cholesterol, which could raise the risk of heart disease. This study showed that a high-protein diet based on plant protein sources helped to lower LDL, rather than raise it.
What are your thoughts? Could or would you follow a plant-based diet? More next week!