Watch your kidneys, muscles and sugars

Question: I've been following a high-protein diet but I recently read something about this adversely affecting my kidneys? I plan to ask my doctor about this, but do you know of any correlation?

Answer: Good question. There are essentially two different scenarios that we need to address here. The first one involves those with a pre-existing kidney condition. In this instance, following a high-protein diet, and specifically the induction phases of some of the most popular programs, can lead to a steeper decline in function. For these individuals, high-protein diets are not recommended. The second scenario involves people with normal kidney function. There isn't any research indicating that high-protein diets negatively impact these folks, but there's an important caveat here that we can't ignore. How do you know if you have normal kidney function? Do you really know if your kidneys are working as well as they should be? Many with renal insufficiency (an early condition of declining function) are asymptomatic, and completely unaware of the potential for problems down the road.

Unfortunately, most folks don't see a doctor before starting a high-protein diet. Therefore, if you've committed to losing weight with this type of regimen, it might be a good idea to get your labs checked.

Question: I know stretching is incredibly important, but someone told me not to stretch before working out. This doesn't sound right to me at all. Can you clarify?

Answer: Whoever told you this is pretty smart. The main rule to follow is never to stretch cold muscles. Warm them up first. We all grew up with the notion that stretching prior to exercise would loosen up our muscles and help prevent injuries; however, recent research has proven otherwise. It now is generally accepted that doing static stretches prior to a workout will likely make you slower and weaker during your exercise sessions and might actually increase your risk for injury. Your best bet would be to do a light to moderate intensity warm-up and then some active, sport-specific movements beforehand to adequately prepare your muscles for work. Then, you can focus on stretching after your workout, when your muscles are warm and much more receptive to a good stretch.

Question: I've noticed that sugar alcohols appear on the labels of some of my favorite foods. What are they and do I need to count them as traditional sugars when tracking my calories and carbohydrates?

Answer: Sugar alcohols are basically hydrogenated carbohydrates and often are used to replace table sugar in a wide variety of foods. In general, they are not as sweet as regular sugars and typically contain fewer calories as well. This is because they are incompletely absorbed in the small intestine, which makes them popular additions to many different diet and diabetic foods. On average, sugar alcohols provide about two calories per gram consumed, as opposed to traditional sugars, which provide 4 calories per gram. It's important to note that some of them (sorbitol and mannitol specifically) can cause gastrointestinal upset in high doses, but people also can develop a tolerance to these issues over time. Some sugar alcohols are classified as food additives, while others have been given GRAS status by the FDA, which means they are Generally Recognized As Safe. The most common sugar alcohols include sorbitol, xylitol, maltitol, mannitol and erythritol.

Ed. note: This is the first in a monthly series of fitness articles by Jay and Heidi Bryan.

Jay Bryan has a master's degree in human performance from the University of Wisconsin-LaCrosse and is certified by the American College of Sports Medicine as a preventive and rehabilitative exercise specialist. With 22 years experience in the health and fitness industry, he has worked in the following settings: corporate health and fitness, health clubs, cardiac rehabilitation, physical therapy, and three years of research at the University of Washington in its Fitness and Aging Project during the early 1990s.

Heidi Bryan started as a physical therapist's aide and now holds several certifications including the certified personal trainer designation from the National Academy of Sports Medicine, and the same from the American Council on Exercise. She has 14 years experience in the fitness field. Jay and Heidi own and operate Anytime Fitness in Sequim.

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