Google "Paleo diet" and you’ll need to sift through more than 5 million hits about how to eat like our Paleolithic ancestors to live longer, healthier and leaner. Since I’m a CrossFit instructor and dietitian, I get asked all the time whether or not Paleo diets work. Results from one of the first human clinical trials with post-menopausal women suggests that a Paleo approach resulted in losing 10 pounds in five weeks and improvements in biomarkers for health.
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Paleo, also called caveman, Stone Age, Neanderthal, primal or ancestral diets, have been all the rage for the past several years. There are several variations on the theme, but the basic tenets include avoiding most carbohydrate-rich foods like sweets, breads, pasta and other grain-based foods, as well as all packaged foods and dairy products. The diet is considered by many nutrition and public health professionals to be a fresh take on the Atkins or South Beach low-carb, high protein diets of the past, although both of those diets include processed foods (as long as they’re protein-rich and carb-poor) and dairy products and are more about caloric-restriction rather than eating wholesome real foods like the primal approach takes.
The Paleo premise is that we should eat the way that we are best genetically suited and that would be what cavemen ate 10,000 years ago. Problem is, researchers can’t agree on what they ate because it varied based on where one lived in the world. Some scientists argue that a diet that’s best for our genes is closest to our living relatives—chimps! The diets of chimps are virtually all vegetarian, with the odd bird or lizard snack. And studies show that vegetarians generally live longer and are thinner than those who follow any other type of modern day eating pattern.
For the most part, a Paleo prescription calls for copious amounts of vegetables, lean proteins, tree nuts and vegetable fats. Anything that was available in the pre-agricultural revolution is ok. While most popular Paleo books promote bacon, beef and burgers over bagels, some research suggests that cavemen were probably more likely to be vegetarians than hard-core carnivores. According to published research in the Proceedings of the National Academy of Sciences, DNA evidence suggests that grains and fermented foods were part of some of our ancestors’ diets. That said, since Americans eat too many processed, sugar- and calorie-rich foods, a Paleo diet will eliminate those choices.
Since there are few published human clinical studies showing that Paleo diets provide lasting weight loss or that they’re heart-healthy, researchers in Sweden set out to evaluate the effectiveness of a Paleo diet for overweight postmenopausal women. Ten overweight, postmenopausal women enrolled in the study and were instructed on how to follow a Paleo diet. The diet provides 30% of calorie from protein (about double of the typical us diet); 40% fat; and 30% of calories from carbohydrates. In essence, they swapped out carbohydrates for protein and healthy, unsaturated fat from primarily canola and olive oil.
Not only did the researchers look at pounds, inches and percentage of body fat lost, they also monitored blood levels of glucose, insulin and cardiovascular biomarkers like LDL and HDL cholesterol. To measure harmful fat that deposits within one’s liver and muscles, all the subjects underwent MRI scans to detect fatty liver and fat levels in muscles.
The Paleo group was instructed to eat primarily lean meats, seafood and poultry; vegetables (including root vegetables); eggs and nuts. Dairy, cereals, beans and processed fats and sugary foods were off limits. So too were all sodas, baked goods and other treats. They were also advised to drink no more than two glasses of red wine per week. They were not told to limit the amount of what they could eat, but to stick to the foods allowed.
After five weeks, the subjects we reevaluated and the researchers found that the average weight loss was 9 pounds and what’s more, they lost 7% off their waists, which is the most harmful area to carry extra weight. In terms of liver fat, that was also reduced by nearly 50%, and excess liver fat (called fatty liver) is a major contributor to several types of chronic diseases, like heart disease and type 2 diabetes. In addition, despite the higher-fat content of the diet, their cholesterol levels improved, triglycerides and blood glucose dropped, insulin levels declined and much more.
While eating Paleo, the subjects naturally reduced their normal calorie intake by just 22 percent, but because of the high protein and low carbohydrate content, the researchers say that is what contributed to the dramatic differences in fat losses and improvements in health risk factors. In addition, since the subjects were allowed to eat as much as they wanted, this study suggests that a Paleo-style that is protein-rich and lower in carbohydrates may help curb hunger while reducing calories.
Bottom line: This is a small study that shows short-term benefits of eating a Paleo diet, but more studies are needed and especially those that show it is a diet that can be followed for life. If you want to try a Paleo approach to weight loss, use these 9 Paleo Principles for modern women. In doing so, chances are you too will probably start to peel off pounds because you won't be eating and drinking foods and beverages with added sugars or other blood sugar-raising carbs that keep us less satisfied and stimulate hunger. While filling a diet with more protein and fewer carbs in general, satiety will be enhanced. Plus, these principles can generally be followed for life, and that is the key to living a lean life.
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