By Dr. Mercola
Could it be that the number of calories you burn in a day is more dependent on your biological roots than the number of minutes you spend being physically active?
Intriguing new research has indeed shown that it's possible human metabolic rates are more evolutionary in origin than a reflection of our modern lifestyles – confirming that what you choose to eat could be the most important factor in your risk of becoming overweight or obese.
Hunter-Gatherers Burn the Same Number of Calories as the Average American
The Hadza tribe of Tanzania still leads an ancient lifestyle that includes daily hunting and foraging for berries, roots and fruit. It's all done on foot, using bows, digging sticks and axes – no guns. Clearly, this is a high level of physical activity that would, according to current beliefs, burn a far greater number of calories than, say, sitting at a computer for eight hours.
What the new research found, however, was that even though physical activity levels were greater among the Hadza people, the average daily energy expenditure was no different than that of Westerners! In other words, even though tribe members spent many hours trekking long distances to hunt and forage for food, they still expended no more calories each day than adults in modern Europe and the United States.
Upending the long-held science of metabolism, the findings indicate that daily energy expenditure may be an "evolved physiological trait largely independent of cultural differences."
Of course, what this means to modern man is that eating more than the number of calories most human bodies are "wired" for could mean you'll gain weight – even if you're exercising religiously. Study author Dr. Herman Pontzer of the department of anthropology at Hunter College, New York told the BBC News:1
"This to me says that the big reason that Westerners are getting fat is because we eat too much - it's not because we exercise too little. Being active is really important to your health but it won't keep you thin - we need to eat less to do that."
Your Diet is More Important Than Exercise for Losing Weight
As I've been saying for years, about 80 percent of your ability to reduce excess body fat is determined by what you eat, with the other 20 percent related to exercise and other healthy lifestyle habits such as sleep and stress reduction. What this means is that if your diet is based on sugar/fructose and processed junk food, it's highly likely that your weight is going to become an issue.
About one-third of U.S. adults fall into the obese category, and a staggering two-thirds or more of Americans are overweight. Dietary culprit #1 is easily fructose, sugars and grains. According to the 2010 Report by the Advisory Committee on the Dietary Guidelines for Americans,2 the top 10 sources of calories in the American diet are:
1. Grain-based desserts (cakes, cookies, donuts, pies, crisps, cobblers, and granola bars) 139 calories a day 6. Alcoholic beverages 2. Yeast breads, 129 calories a day 7. Pasta and pasta dishes 3. Chicken and chicken-mixed dishes, 121 calories a day 8. Mexican mixed dishes 4. Soda, energy drinks, and sports drinks, 114 calories a day 9. Beef and beef-mixed dishes 5. Pizza, 98 calories a day 10. Dairy desserts
Looking at this list detailing the top sources of calories in the American diet, it's easy to recognize that the dietary roots of the American weight problem is linked to carbs—sugars (primarily fructose) and grains—in the form of processed foods and sweet drinks. If it's true that we burn about the same number of calories a day as Tanzanian hunter-gatherers who are physically active at a level only the most dedicated of athletes in America likely attain – then the reason why so many Americans are overweight while the hunger-gatherers are lean comes down to food choices.
I believe the two primary keys for successful weight management are severely restricting carbohydrates (sugars, fructose, and grains) in your diet, and increasing healthy fat consumption. This will optimize insulin and leptin levels, which is key for maintaining a healthy weight and optimal health. For more details, I suggest you review my Optimized Nutrition Plan, which is a comprehensive and step-by-step guide to help you make health-promoting food and lifestyle choices. This includes:
Limit your fructose to less than 25 grams per day, and, ideally to less than 15 grams per day, as you're likely consuming 'hidden' fructose if you eat processed foods or sweetened beverages Limit or eliminate all processed foods Eliminate all gluten, and highly allergenic foods from your diet Increase the amount of fresh vegetables in your diet, and consider juicing Eat at least one-third of your food uncooked (raw), or as much as you can manage Avoid artificial sweeteners of all kinds
Should Your Diet Mimic the Hunter-Gatherers'?
During the Paleolithic period many thousands of years ago, people ate primarily vegetables, fruit, nuts, roots and meat—and a wide variety of it. Today, these staples have been largely replaced with refined sugar, high fructose corn syrup, cereal, bread, potatoes and pasteurized milk products… and a much narrower selection of fruits, vegetables, roots and nuts.
While we may consider ourselves to be at the pinnacle of human development, our modern food manufacturing processes have not created a race of super-humans in possession of great health and longevity. Humans today suffer more chronic and debilitating diseases, including obesity, than ever before. And there can be little doubt that our food choices play a major role in this development. By eating foods that are concordant with your genetic ancestry, you can avoid many of the diseases associated with our modern diet, including obesity, diabetes, heart disease and cancer.
You can actually mold your diet around the principles of Paleo eating rather easily by following my nutrition plan.
Episodes of intermittent fasting may also be important, as our ancestors clearly did not have access to food on a 24/7 basis like we do today. I believe it to be one of the most profound interventions for the 21st century. Quite simply, we've strayed too far from the foods we are designed to eat, so going back to basics and refocusing your diet on fresh, whole, unprocessed, "real" food can improve just about anyone's health. In addition to the points noted above, a "healthy diet" is qualified by the following:
- Unprocessed whole foods
- Organic or grass-fed, and free from additives and genetically modified ingredients
- Comes from high-quality, local sources
- Carbohydrates primarily come from vegetables (except corn and potatoes, which should typically be avoided)
Should You Exercise Like the Hunter-Gatherers Too?
While your diet may be the driving factor behind your weight, exercise is still an essential component of good health, fitness and longevity. Interestingly, just as a hunter-gatherer diet may be beneficial, there's a lot to be said about moving like a hunter-gatherer too. Instead of being sedentary for much of the day and then running for an hour on a treadmill, our ancient ancestors combined lots of walking with regular lifting and short bursts of high-intensity activities, and health experts agree that this may be a healthier way to live because this is what your body is "wired" for.
My Peak Fitness program incorporates this essential factor, which is, I believe, why so many people have achieved such great results with it. A summary of what researchers believe might be an ideal exercise prescription would include the following aspects of normal hunger-gatherer living:
A variety of exercises performed regularly (weight training, cardio, stretching, etc.) Alternate difficult days with easier days Exercise outdoors, which helps maintain vitamin D levels and improve mood Peak Fitness sessions performed no more than three times a week Weight training 2-3x a week Walk and run on softer, uneven terrain, such as grass and dirt, possibly barefoot or using "simpler shoes that do not drastically restrict foot motion or alter natural foot strike dynamics" Exercise with a friend to receive social stimulation as well Ample time for rest after physical exertion Recreational activities, including dancing and sex