This study is a big deal. It shows that high-carb, plant-based diets work out in the real world where people are pressed for time, don’t have a lot of money* or cooking expertise, don’t want to feel hungry or be denied in other ways:
The BROAD Study: A Randomised Controlled Trial Using A Whole Food Plant-Based (WFPB) Diet In The Community For Obesity, Ischaemic Heart Disease Or Diabetes, Nutrition and Diabetes, 20 March 2017
Conclusions: This programme led to significant improvements in BMI, cholesterol and other risk factors. To the best of our knowledge, this research has achieved greater weight loss at 6 and 12 months than any other trial that does not limit energy intake or mandate regular exercise.
I want to repeat that … the diet did not limit calories. No weighing or measuring or fretting over serving sizes. Participants ate until they were satisfied (ad libitum).
The key difference between this trial and other approaches to weight loss was that participants were informed to eat the WFPB diet ad libitum and to focus efforts on diet, rather than increasing exercise. The mechanism for this is likely the reduction in the energy density of the food consumed (lower fat, higher water and fibre).
They lost weight (mean weight loss at 6 months was 26 lbs, dropped from 209 to 183 lbs), lowered their BMI and waist circumference, lowered their cholesterol (from 209 to 174 mg/dl in 3 months), lowered their blood glucose. How can this not be a good diet?
This is what they were eating:
Intervention participants followed a low-fat plant-based diet (approximately 7–15% total energy from fat). We chose a low-fat iteration of the plant-based diet as this has been shown with previous research to achieve optimal outcomes, especially for heart disease and weight loss. This dietary approach included whole grains, legumes, vegetables and fruits. Participants were advised to eat until satiation. We placed no restriction on total energy intake. Participants were asked to not count calories. We provided a ‘traffic-light’ diet chart to participants outlining which foods to consume, limit or avoid (Supplementary Table S1). We encouraged starches such as potatoes, sweet potato, bread, cereals and pasta to satisfy the appetite. Participants were asked to avoid refined oils (e.g. olive or coconut oil) and animal products (meat, fish, eggs and dairy products). We discouraged high-fat plant foods such as nuts and avocados, and highly processed foods. We encouraged participants to minimise sugar, salt and caffeinated beverages. We provided 50 μg daily vitamin B12 (methylcobalamin) supplements.
Here’s their Supplementary Table S1. It’s just a guide, not a dictum. Click to enlarge:
Since all of these participants were overweight, researchers restricted nuts and seeds. Whole nuts and seeds, as Dr. McDougall explains in his books, can be consumed if weight loss is not a goal. I personally think that a diet with nuts and seeds is better than a diet without them.
In the discussion section, they compared their intervention (WFPB diet) to other interventions, including very-low-calorie diets, gastric bypass surgeries, and low-carb diets. This is what they said about low-carb diets:
However, studies on the effects of low-carbohydrate diets have shown higher rates of all-cause mortality, decreased peripheral flow-mediated dilation, worsening of coronary artery disease, and increased rates of constipation, headache, halitosis, muscle cramps, general weakness and rash.
I keep saying … low carb diets may help you lose weight, but you mortgage your health doing it.
Eat starch. Eat carbs. You’ll lose weight. You’ll lose your diabetes, blood pressure, cholesterol meds. You’ll lower your risk for cancer. You’ll feel better. The thing people do to muck this up is eat the carbs with fat and animal food. Totally negates the benefit, as I’ve discussed in my various “meat-and-potatoes” posts.
* “The intervention involved patients from a group general practice in Gisborne, the region with New Zealand’s highest rates of socioeconomic deprivation, obesity and type 2 diabetes.”