Burning Fat – Myths and Facts
October 19, 2010
A popular myth is that there is a specific range of heart rates in which you must exercise to burn fat. Even many cardio machines display a “fat-burning zone” on their panels, encouraging people to exercise in a specific heart rate range. Have you ever wondered if you really have to exercise in a specific heart rate zone to lose fat? And what happens if you venture out of that zone? Jason R. Karp, PhD , a nationally recognized speaker, writer and exercise physiologist who coaches recreational runners to Olympic hopefuls through his company, RunCoachJason.com, sheds light on this issue.
FUEL USE DURING EXERCISE
You use both fat and carbohydrates for energy during exercise, with these two fuels providing that energy on a sliding scale. During exercise at a very low intensity (e.g., walking), fat accounts for most of the energy expenditure. As exercise intensity increases up to the Lactate Threshold (the exercise intensity that marks the transition between exercise that is almost purely aerobic and exercise that include a significant anaerobic contribution; also considered the highest sustainable aerobic intensity), the contribution from fat decreases while the contribution from carbohydrates increases. When exercising just below the lactate threshold, you are using MOSTLY carbohydrates. Once the intensity of exercise has risen above the lactate threshold, carbohydrates become the ONLY fuel source.
If you exercise long enough (1.5-2 hours), your muscle carbohydrate (glycogen) content and blood glucose concentration become low. This metabolic state presents a threat to the muscles’ survival, since carbohydrates are muscles’ preferred fuel. When carbohydrates are not available, the muscles are forced to rely on fat as fuel.
Since more fat is used at low exercise intensities, people often assume that low-intensity exercise is best for burning fat, and idea that has given birth to the “fat burning zone.” However, while only a small amount of fat is used when exercising just below the lactate threshold, the rate of caloric expenditure and the total number of calories expended are much greater than they are when exercising at a lower intensity, so the total amount of fat used is also greater.
THE BOTTOM LINE
For fat and weight loss, what matters most is the difference between the number of calories you expend and the number of calories you consume. Fat and weight loss is about burning lots of calories and cutting back on the number of calories consumed. For the purpose of losing weight, it matters little whether the calories burned during exercise come from fat or carbohydrates.
This article is a service of IDEA, for copy and distribution. IDEA is the leading international membership association in the healthy and fitness industry.
Processed Meat Mash
October 6, 2010
This article below was found in an email going around – it is absolutely frightening, and will definitely make you think twice about processed meats. Yikes!! Not for the faint stomach.
The photo above has been extensively passed around recently, and for good reason: it’s a peek into the rarely-seen world of mechanically separated meat, or Advanced Meat Recovery (AMR).
Fooducate writes:
Someone figured out in the 1960s that meat processors can eek out a few more percent of profit from chickens, turkeys, pigs, and cows by scraping the bones 100% clean of meat. This is done by machines, not humans, by passing bones leftover after the initial cutting through a high pressure sieve. The paste you see in the picture above is the result.
Michael Kindt continues:
There’s more: because it’s crawling with bacteria, it will be washed with ammonia… Then, because it tastes gross, it will be reflavored artificially. Then, because it is weirdly pink, it will be dyed with artificial color.
But, hey, at least it tastes good, right?
High five, America!
The resulting paste goes on to become the main ingredient in many of America’s favorite mass-produced and processed meat-like foods and snacks: bologna, hot dogs, salami, pepperoni, Slim Jim-like jerkys, and of course the ever-polarizing chicken nugget, where the paste from the photo above was likely destined.
Athletes and Protein
October 3, 2010
As an athlete, you want to make sure you fuel your body in a way that supports performance in your sport – and life. How much and what kind of protein is best?
Natalie Digate Muth, MD, MPH, RD, a graduate of University of North Carolina School of Medicine, a registered dietitian and an American Council on Exercise master trainer, offers practical tips on how to choose protein sources.
Protein Quality
Several scales are used to evaluate protein quality. However, the most widely used and most accepted method is scaled the protein digestibility –corrected amino acid score (PDCAAS). The proteins with the highest (i.e., best) PDCAAS scores are whey, casein, egg, milk, and soy proteins (Hoffman & Falvo 2004). Beef comes in next, followed by black beans, peanuts and wheat gluten (Hoffman & Falvo 2004). Fruits vegetables, grains and nuts are incomplete proteins and must be combined over the day to ensure adequate intake of each of the essential amino acids.
Choosing the Right Protein Sources
While no one type of protein is best for everyone, bear these points in mind:
Protein Does Not Exist in a Vacuum.
Remember that other that macronutrients also come into play. For example, while beef is a fairly good protein source, it is also high in saturated fat and calories. For example, a 6-ounce broiled porterhouse steak contains 38grams (g) of protein, but it also delivers 44g of fat, 16 of them saturated – almost three-fourths of the recommended daily intake for saturated fat. The same amount of salmon gives you 34g of protein and only 18g of fat, 4g of them saturated (Harvard School of Public Health 2009).
Different Proteins Are Better at Different Times
For example, whey protein is digested rapidly, resulting in a short burst of amino acids into the blood stream, whereas casein is digested slowly, resulting in a more prolonged release of amino acids (Dangin et al. 2002) If the goal is for amino acids to be available for muscle regeneration immediately following a workout, you should time your protein intake accordingly.
A High-Protein Diet Is Not for Everybody
Individuals with pre-existing illnesses such as kidnbey disease, osteoporosis, diabetes or liver disease should consult with their physician prior to adoptinbg a high-protein diet (St. Jeor et al. 2001).
Protein Recommendations for Athletes
Resistance training and cardiovascular exercise induce beneficial muscular and structural damage. Because protein helps the muscles and tissues repair and rebuild themselves, the American Dietetic Association (ADA), Dietitians of Canada (DOC), and the American College of Sports Medicine (ACSM) suggest that athletes have higher protein needs than the general population. These agencies advise endurance athletes to consume about 0.5-0.6 grams per pound (g/lb), whereas strength-trained athletes should consume up to 0.6-0.7g/lb (ADA, DOC, ACSM).
The recommendations are even higher in specific sports such as bodybuilding, fitness, or figure athletes. The protein intake is even greater – approximately 1-2g/lb – depending on how much size and muscle the athlete is trying to add.
Courtesy of the IDEA Fitness Handout.
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