Last week at the Obesity Week 2018 conference, two expert nutritionists debated the question: which is better, plant based or meat based diet.

Pro Meat: Wayne Campbell, Ph.D. Purdue University

“There is no such thing as a “semi-vegetarian.” That is either a bad vegetarian or an uncommitted carnivore!” - Dr. Campbell

Dr. Campbell began by pointing out that most dietary guidelines are not guided by scientific evidence - these panels do their best, but the quality of evidence is poor. The Dietary guidelines of America limit red meat to 1.5 ounces a day and you cannot eat all 1.5 oz at once. Dr. Campbell claimed this recommendation is founded in no meaningful evidence, nor is the advice to limit meat to monthly as seen in the Mediterranean diet pyramid is not based on evidence. To the concern that meat causes cancer, he also pointed out that the American Institute for Cancer Research shows that 18 ounces of red meat weekly does not increase cancers.

Next, Dr. Campbell reviewed the scientific literature to determine if consuming red meat negated the health benefits of weight loss or the improvement in cardiovascular health indicators seen with weight loss (i.e. if a person eats red meat and their weight, blood pressure, and blood sugar improve, does the fact that it was done by eating red meat negate the expected benefits?). He found that people who ate meat experienced reduced cravings which increased the amount of weight loss for those enrolled in a weight loss plan. He also noted improvement in cardiovascular indicators compared to a simple “calorie restricted” diet.

He ended his argument with the notion that processed meats are the problem. Processing meat makes it very hard (impossible in fact) to stay within recommended guidelines for sodium, saturated fat, and calories. He presented a table comparing lean pork to a breakfast sausage. The sausage had 10+ ingredients and included outrageous amounts of sodium, saturated fat, calories.  Further, it is the processing of meat that has been recognized as a cause of cancer.

Pro Plant: Gabrielle Turner-McGrievy, Ph.D., University of South Carolina

Dr. Turner-McGrievy first admitted she was a vegan and is very active in promoting veganism. She admits there is little good scientific evidence to argue against a non-meat diet, but enough circumstantial evidence to suggest current American diets, which are heavy in meat, are not generating results either. She acknowledged there is limited research on adherence to one singular diet; complete adherence may not be needed for benefits.

Dr. Turner-McGrievy began by reviewing the literature. She points out that plant based diets don’t always “win” in health comparisons but they rarely “lose”. She cited a study that studied a low carbohydrate, vegetarian and reported in favored metabolic health outcomes compared to all other diets. She argued that beans are a viable protein alternative to meat in most cases and demonstrated solid evidence to support this claim. Lastly, she showed that when cheese was high in diet showed adverse health effects, likely from the saturated fat. This last study does not argue against meat so much as it argues in favor of a vegan based diet.

Regarding the positive metabolic impact in favor of a vegan diet, people do not have to count calories or keep a food diary to achieve a more normal body weight due to the low caloric nature of plants - it is rare to find obesity amongst vegan populations. Also, plant based diets automatically reduce energy intake so exercise is less necessary to maintain a healthy body weight.

Dr. Sutherland’s take:

How much of the benefit seen with a plant based diet comes from adding plants vs. removing meat?  My preferred diet is both: plant based diet with some fresh, plain, unprocessed meat thrown on top! Best of both worlds! You only have to remove sugar and processed carbohydrates and grains to make room for the plants.  The fiber and phytonutrients are there! There is no ONE “healthy” diet, but you cannot go wrong eat real food that looks like it did when your great grandparent ate it, with very few ingredients and that does not come in a package with a bar code!

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