In the study, conducted at the German Institute of Human Nutrition in Berlin, men and women were divided into two groups eating protein-rich diets: One ate animal-based protein from meat and dairy, and the other ate plant-based protein from sources such as lentils and chickpeas. Both groups got the rest of their nutrition from 40% carbohydrates and 30% dietary fat (the same ratios as in the Zone Diet). After 6 weeks, all participants had improved glucose metabolism and reduced liver fat, but the animal-protein group also showed better insulin sensitivity, and the plant-protein group showed better kidney function.
These results don’t surprise J. Michael Gonzalez-Campoy, MD, who sees the power of healthy eating every day as medical director and CEO of the Minnesota Center for Obesity, Metabolism and Endocrinology (MNCOME). Here’s how it works: “The normal trigger for insulin release is a rise in plasma glucose,” he explains, “which happens after eating carbohydrates that have a high glycemic index—they turn to glucose in the blood readily—such as potatoes, beans, rice, pasta, and sweets.” Eat these foods in abundance and you could develop chronic insulin stimulation. In turn, a high insulin level over time has many effects in the body, including the birth of new fat cells (to accommodate the excess energy) and more fat storage in existing fat cells. At some point, the body has to start stashing fat in other organs, including the liver.By contrast, when you fill your plate with protein instead of soluble carbohydrates (foods high on the glycemic index), the body secretes less insulin and this whole process is reversed. “Intake of foods lower on the glycemic index improves metabolic function over time,” says Gonzalez-Campoy, “and this leads to improved cardiovascular disease risk factors and weight loss maintenance.” (Discover the power of foods that smother diabetes-related inflammation with The Diabetes Cure!)
As far as Gonzalez-Campoy is concerned, the higher-protein, lower-carb meal plan used in the study validates the recommendations issued by the American Association of Clinical Endocrinologists and the Obesity Society in their Healthy Eating Clinical Practice Guideline. “All adults, and especially those with diabetes, prediabetes, insulin resistance, overweight, or obesity—and even those who do not have any of these problems—can benefit from healthy eating,” he says. “The meal plan in this study is a healthy plan that would benefit anyone.”
Bringing It Home
We asked two registered dieticians who specialize in diabetes to devise a typical day’s menu on a “30% protein, 40% carbohydrates, and 30% fat” meal plan—the same ratio of macronutrients as those used in the German study. Gonzalez-Campoy stresses that however you mix it up, 10 to 35% of your daily calories should come from protein.
Breakfast: ½ whole wheat English muffin with 1 Tbsp trans fat–free margarine spread, 1 hard-boiled egg, and 1¼ cup strawberries
Snack: 5 to 6 oz nonfat fruit-flavored Greek yogurt with 1 Tbsp chopped nuts
Lunch: Roast beef sandwich made with 1 small (1-oz) whole wheat pita bread, 3 oz low-sodium lean roast beef, 2 slices red onion, and lettuce; plus ¾ cup carrots and ⅓ cup hummus
Snack: ⅓ cup cut pineapple with 1 cup low-fat cottage cheese.
Dinner: Chicken and vegetable stir-fry made with 8 oz raw chicken breast strips, ½ cup snow peas, ½ cup water chestnut slices, ¼ cup chopped green onion, and ½ cup mandarin oranges (canned in juice), stir-fried in 1 Tbsp peanut or canola oil, 1 Tbsp low-sodium soy sauce, and a minced garlic clove. Served over 1 cup cooked brown rice.
Breakfast: Frittata made with 1 cup liquid egg whites, ⅛ cup shredded cheese and veggies; plus Greek vanilla yogurt (5 oz)
Lunch: Tuna nicoise salad (using 4 oz tuna) with a low-calorie Italian dressing; 10 whole grain crackers; 1 cup fresh berries topped with frozen whipped topping
Snack: Peanut butter and banana sushi (spread 2 Tbsp peanut butter on a low-carb tortilla and lay a small banana on top, roll tortilla and slice into bite-size pieces)
Dinner: 4 oz grilled chicken with a squeeze of lemon, ¾ cup rice pilaf with currants, steamed green beans with roasted red pepper, 1 small whole grain roll, 1 tsp butter or buttery spread
Snack: 25 pistachio nuts