Exercise and Research

Exercise enthusiasts have routinely been challenged by the best way to spend their time in the gym when the primary goal is fat loss. Historically clinical trials have supported aerobic exercise as having the greatest impact on total fat mass but with a consequent loss of lean mass in the process. Similar trials have supported the addition of resistance activities to cardiovascular exercise programs aimed at caloric expenditure and an improved body compositional outcome. Although both have demonstrated effectiveness at fat loss, practitioners are now concerned not only with fat loss but also where that fat is derived from. Obesity in the United States has reached an all-time high, jumping more than 10% in most States since just 1990. With the growth of the nation comes the increase of cardio-metabolic disease stemming from the high levels of visceral adiposity. Central fat storage is associated with inflammatory chemicals; a major contributor to disease. Although visceral adiposity is more metabolic the best way to reduce it has not been addressed. In a recent article published in the Journal of Sports Medicine and Physical Fitness (2010) researchers analyzed the affects of endurance training versus concurrent endurance/resistance training on measures of total and regional fatness in sedentary males. Following 16 weeks of treatment, subjects were measured for body fatness, body mass index, waist circumference, and waist to stature ratio. With changes to measures collectively reported, the endurance group as a whole reduced fat mass by 27% and body fat percentage 31%; the endurance/resistance group reduced fat measures by 32% and body fat percentage 30% respectively. When localized fat mass was reviewed the endurance/resistance group collectively reduced waist circumference by 3% and waist to stature 4%, whereas the endurance group reduced the waist circumference by 2% and the waist to stature ratio 2%. These findings suggest that although endurance training is effective for fat loss, utilizing resistance training as part of the regimen improves fat loss from central locations. Personal trainers can use this information to emphasize programs that address weight loss and central adiposity simultaneously.

New Heart Rate Max Formula Published (for women)
According to Dr. Martha Gulati M.D., assistant professor of medicine and preventive medicine and a cardiologist at Northwestern Medicine, women have been inaccurately attempting to calculate maximum or peak heart rate using the traditional (220-age) formula. As published in the Northwestern University Newsletter (June, 2010), "Women are not small men; there is a gender difference in the exercise capacity a woman can achieve. Different physiologic responses can occur." The data used for the new formula was based on the findings from the St. James Women Take Heart Project, a study of 5,437 healthy women, ages 35 and older which began in the Chicago area in 1992. The study was published in the journal Circulation (2010). According to Gulati, the new formula provides a more accurate estimate of the peak heart rate a healthy woman should attain during exercise. It also will more accurately predict the risk of heart-related death during a stress test. Due to the fact that the Heart Rate Max Formula is based on studies of men the newer formula better addresses the sex differences that affect the heart and circulation including heart size, blood volume, lean and total mass. The new formula for women, based on the new research, is 206 minus 88 percent of age. This suggests that a 45 year-old female would have a predicted max heart rate of 166 beats • min-1 using the new formula, compared to the original formula’s prediction of 175 beats• min-1. These finding may, in part explain the prediction error found in the original formula. These findings also suggest that females who were training at the high end of the previous 75-90% of max heart rate, or 60-80% of their predicted heart rate reserve were potentially over conditioning. A second question bears, does the published accuracy transfer to those females outside the ages in the study (under 35 years). Gulati is currently working on an iPhone application to make the calculation easier to use since the Heart Rate Max equation became a bit more difficult.

A Pound of Muscle Burns 30-50 Kcal/Day Really...

Two “expert” fitness websites contradict each other – according to one “each additional pound of muscle equates to an increase of 50 kcal of resting metabolism each day” but the other online site suggests “you will burn an additional 30 calories a day by adding a pound of muscle mass.” Which is correct? As you may expect from the internet, neither website is correct. Presumably these inflated numbers come from antiquated studies with poor conclusions that looked at the effects of resistance training on muscle mass gains and metabolism. Several early studies demonstrated gains of 1.5-2 kg of lean mass in untrained individuals performing resistance training for 8-12 weeks. The metabolic result was a daily increase of 200-300 calories above previous measured daily expenditure. Doing some simple math, if a person added 3 pounds of muscle and burned 240 calories more per day the net gain would be 80 kcals per pound. But this would not be the doing of lean mass alone.

Working out with weights burns calories, as does any movement. To suggest an increase of one or two pounds of muscle equates to a notable increase in resting metabolic rate would be inaccurate. Muscle has a low metabolic rate compared to other metabolic tissues at rest. It is estimated that sedentary muscle mass burns about 6 kcals per pound/day or 0.25 calories an hour per pound. This number obviously increases with activity relative to the intensity, but looking it at from a metabolic perspective (METS) that number still does not reach 50 kcal per pound. If it did, a 185 lb person would need 3885 calories to sustain their muscle tissue which represents only about 40% of bodyweight. What about the other sixty percent, and the 3885 calories does not take into account the 300 kcal for the brain (109 kcal/lb) or the 400 kcal for the liver (91 kcal/lb) and 125 kcal for kidneys (200 kcal/lb). Add these organs in and this number now is 4710 kcal/day without even counting the highly metabolic heart (200 kcal/lb) or any other tissue including the skin or fat, although the latter provides the lowest metabolic stimulus at about 2 kcals per pound. After it’s all said and done this person would require over 5000 kcal from their diet a day to support rest; imagine if he exercised.

Using a simple formula to look at the oxygen demands of tissue exemplifies the limited calories expended per pound of muscle. Working muscles use carbohydrates as a primary fuel for more intense exercise. Therefore, applying the concept that lean tissues burns 5 kcal per liter of oxygen when used with carbohydrates, the metabolic rate of the tissue can be calculated during activity. Consider 60 minutes of exercise at a 10 MET intensity.

1 lb of muscle = 0.45 kg lean mass x .035 L (10 METS) x 60 min x 5 kcal/L = 4.7 kcal/hour per pound

This equates to approximately 350 kcals for total muscle mass if used in a workout. Since we do not use total musculature continuously in a 60 minute workout this number is inflated, but the other tissues make up for the difference. During cross country skiing for example, the muscles can require 60-70% of cardiac output, but at rest only 15%. At rest, the metabolic organs actually contribute heavily to metabolism and use a higher percentage of cardiac output (about 50%). Even bone receives more than 10% cardiac output at rest. It is the workouts and other physical activities engaged in during the day that raise the metabolic rate of muscle to the roughly 11 kcals per pound suggested in exercise physiology textbooks. Part of the reason that muscle only does so much to promote metabolic expenditure in a day is the body is at rest for the majority of the time. If it burned high levels of calories at rest, early humans would have constantly been searching for food or would have starved to death. Although representing only about 6% of bodyweight, the metabolic organs contribute much more dramatically to resting expenditure than the quantifiably heavier muscle and fat tissue.

The muscles though, do provide a metabolic boost during rest in the recovery of exercise. This “after burn” or more correctly excess post exercise oxygen consumption occurs in response to the physiological disruption in the tissue. Post exercise, muscles and organs are drained of energy and require replenishment, the heart must continue to work to supply oxygen to ischemic tissues and to help promote byproduct removal in the fast component of the process. A slower component that lengthens the durations of recovery is the imposed rate of protein turnover associated with higher intensity training, particularly from high tension anaerobic exercises like squats and deadlifts. Most forms of resistance exercise will increase protein turnover albeit body building, strength training, or conditioning drills such as plyometrics and all will increase calorie expenditure in the hours that follow based on tension and total volume.

Therefore adding muscle is just as important as training the current muscle that exists on the body. This explains why clinically supervised weight loss programs emphasize the maintenance of lean mass. Losses of lean mass during the “dieting” process reduce the caloric contribution of muscle and just 10 kcals/day equates to the metabolic equivalent of one pound of fat in a year. Looking at the numbers from a day to day perspective devalues the tissues impact over time. To defend against this risk many with the goal of weight loss increase protein intake to preserve muscle.

This is where a second fitness fallacy comes into play. Many exercisers increase protein to maintain or add lean mass. But consumed protein does not equate to gained lean mass. Excess protein in the diet follows a preferential path to triglyceride formation. Eating more protein only ensures more nitrogen enters the body which often requires more water to excrete it. The same muscle websites that tell you adding a pound of muscle contributes to 50 kcal of resting metabolism are the ones suggesting a person needs a gram of protein per pound to add muscle mass.

Muscle tissue really only needs a relatively small amount of added protein to promote the process of remodeling. An intake of 1.6 grams per kilogram of body weight easily supports this goal without crossing the tolerable upper limit (UL). Certainly body builders who take steroids can utilize more protein because they have the internal environment to use it, but the need for a personal training client is much reduced in comparison. Consider this, a pound of muscle weighs 454 g and is composed of 22% protein. This equates to about 100 g of protein in a pound of muscle. Therefore to add a pound of muscle in a week (assuming appropriate training and anabolic activity) a person would need only 100 additional grams of protein per week or 14 g per day (56 kcal). To add mass the body actually needs calories, about 400-500 extra a day to add a pound of muscle a week. But that does not mean all the calories should come from protein and the added calories also usually means added fat as well. When put into perspective the same 185 lb person would only need 75 g of protein a day if sedentary, and if he suddenly became an avid weightlifter would require 134 g of protein per day or an increase of 59 g from his sedentary requirement. This jump in protein includes any additional muscle building needs.

Interestingly though, many exercise programs attempt to emphasize adding muscle mass to help reduce fat mass and use cardiovascular exercise and restricted diet to reduce body fat at the same time. Based on the above this should sound counterintuitive. To add mass you need calories, to lose mass you need to remove calories. Deconditioned people and those who are anabolically enhanced are really the only ones who lose fat while they add muscle and the prior will add a relatively small amount before leveling off quickly. Based on this information weight loss programs may benefit from a periodized approach where at one point they emphasize caloric expenditure with a goal of maintaining mass (which also speaks to improved cardiovascular and anaerobic endurance conditioning) before focusing on adding mass whilst trying to limit fat gain. For the obese the goal should be physical activity in general, to manage the likely inflammatory problems and for those with cardio-metabolic disease an emphasis on health and fitness will complement weight loss. Regardless of the population being addressed, having a better idea of the dynamics that affect metabolism and body mass certainly aid in finding a level of success in managing it.

6 Reasons Why We Don't Lose Weight

By John Messmer, MD

Doctors hear this complaint often: “I’m dieting all the time, but I can’t lose any weight.” For many people, losing weight is a frustrating endeavor. No matter how hard they seem to be trying, nothing changes. What is going on? Identifying the problem is only part of the solution.

6 common reasons why we don’t lose weight

1. Many of our social interactions include food.
2. Restaurants portions have increased (particularly fast food).
3. We are less active than in the past.
4. We find it unacceptable to be hungry.
5. We misunderstand how weight is maintained.
6. We forget the extra food we eat everyday, or we think we ate less than we did.

It’s also important to remember that when we consume fewer calories, we have a tendency to be less active, which probably stems from our biological programming to preserve body weight for survival.

Simple truths about weight loss

Many people think weight loss is like emptying a bucket with a ladle. A scoop out of the bucket today, tomorrow, next week will eventually empty the bucket. Not so with our bodies. When we decrease our food intake, our bodies try to absorb and store more calories the next time we eat in excess of what our body needs. So, even though we are cutting down most of the time, we will not lose weight if we get extra calories part of the time.

The simple rule of weight loss is that you must consistently burn off more calories than you take in. Any type of weight loss diet can work as long as calorie intake is consistently reduced, every day. A diet that is balanced with small quantities of vegetables, fruit, grains and lean meat or fish is the healthiest. Exercise helps, but unless you are an athlete, you will have to cut calories, too. And remember, it’s OK to be hungry when losing weight. Once a goal is achieved, every day is for maintaining. If you go back to eating more and exercising less, the weight will go right back on.

Factoring exercise into your weight loss plan

You can exercise more to lose weight, but beware of this idea. Most people don’t realize how much exercise is needed to lose weight without cutting calories. Plus, exercise increases appetites. If a dieter can avoid eating any more than was consumed before the diet and can burn off an additional 500 calories every day, that person can lose a pound a week. One mile, walked or run, or five miles on a bike, burns 100 calories. If you can do five miles a day—every day—and not eat any more no matter where you are or what you are doing, you can lose a pound a week. Or, you can cut 250 calories per day and do two and a half miles to accomplish the same thing.

Everyone can lose weight. Not everyone can or should be skinny, but everyone can reach a normal, healthy weight. It requires an acceptance that we cannot eat all we want, whenever we want. We can enjoy food and the occasions in which food is served, but our food intake must be balanced with our activity to achieve and maintain a normal weight.

10 Strategies for permanent weight loss

For many people weight loss is a chronic endeavor. All too often the shedding of pounds is a temporary event followed by a steady regain of lost weight. Most popular diets are unsuccessful in the long run because they fail to address the multi-faceted nature of what successful, permanent weight loss entails. Luckily, research has revealed many invaluable strategies which can help increase your odds of permanent weight loss.

1. Exercise is essential for weight loss

It's nothing new, but exercise is probably the most important predictor of whether you will succeed at long term weight loss and weight loss maintenance. In order for exercise to be helpful in weight loss, you should strive for a minimum of five 30 minute sessions per week. The good news is that recent research has shown that three 10 minute sessions in a day are as good as one 30 minute session. This helps many in combating the old "no time for exercise" excuse. Be certain to find something you enjoy. You'll be more apt to stick with it. Try walking with a friend, joining an intramural sports league, participating in outings with a group like The Sierra Club, or trying some classes at your local gym. Once you give exercise a chance, you will begin to enjoy its positive benefits on your psyche as well; you will literally become "hooked."

2. Weight loss and weight training

We chose to list this separately from the "exercise" category because of the significant weight loss benefits attached to weight training in and of itself. The basic equation is this: the more muscle tissue you have, the more calories you will burn. This is why world class weight lifters must eat thousands of calories a day to maintain their weight. Muscle is active tissue, fat is not. Thus, muscle "burns" a significant number of calories each day for its own maintenance. In her book Strong Women Stay Slim, Miriam Nelson, a Tufts University researcher, showed that a group of women who followed a weight loss diet and did weight training exercises lost 44% more fat than those who only followed the diet. While aerobic activity can help burn calories, muscle's where it's at when it comes to giving your metabolism a significant daily boost even at rest.

3. Keep a diary for triggers that hinder weight loss

Keeping a food diary can be a huge asset in successful weight loss. Devote some time each day to record what you have eaten and how much, your hunger level prior to eating, and any feelings or emotions present at the time. A food diary can provide a large amount of self-awareness. It can identify emotions and behaviors that trigger overeating, foster greater awareness of portion sizes, and help you discover your personal food triggers. Study any patterns that emerge from your food diary and identify where you may be able to make more healthful changes. A food diary provides an added benefit of keeping you focused on and committed to your goals. Start keeping a food diary today by printing our food diary.

4. Stay focused on being healthy, not on becoming thin

Many people become more successful at long term weight loss when their motivation changes from wanting to be thinner to wanting to be healthier. Change your mindset to think about selecting foods that will help your body's health rather than worrying about foods that will affect your body's weight. The Food Pyramid offers a basic outline of the types and amounts of food you should eat each day to give your body the nutrients it needs for optimal health.

5. Find out why you overeat

All too often overeating is triggered by stress, boredom, loneliness, anger, depression and other emotions. Learning to deal with emotions without food is a significant skill that will greatly serve long term weight control. The Solution, a book and national program developed by Laurel Mellin, RD, helps participants to identify their eating triggers and respond to them without food. A research study showed that the participants in this program demonstrated a better rate of long term weight loss maintenance than those who simply diet and/or exercise and don't address behavioral and emotional issues. Chronic over-eaters and "emotional eaters" can be significantly helped by learning new behavioral skills such as those Mellin presents. You can also seek help with behavioral and emotional eating issues from a licensed counselor or psychologist in your area.

6. Weight loss support: join a weight management group

A big key in long term weight control comes from receiving encouragement and support from others. You can check to see if groups such as Jenny Craig offer programs and resources in your areas. You may also wish to check with your local hospital to see if their registered dietitian conducts group weight loss programs.

7. Weight loss and portion control

With the advent of "super-size" meals and increasingly huge portions at restaurants, our concept of normal serving sizes is a distant memory. Be mindful of the amounts of food you consume at a sitting. When necessary, divide your food in half and ask for a take home bag. It is all too easy to be a "plate cleaner" even when served enormous portions. Learn to pay attention to your hunger level and stop eating when you feel comfortably full, not stuffed.

8: Lose weight slowly with small changes

Try to remember that "losing 15 pounds in two weeks" is nothing to celebrate. It is important to realize that the more quickly weight is lost, the more likely the loss is coming from water and muscle, not fat. Since muscle tissue is critical in keeping our metabolism elevated, losing it actually leads to a decrease in the amount of calories we can each day without gaining weight. Fat loss is best achieved when weight is lost slowly. Strive for a weight loss of no more than 1-2 pounds per week. One pound of weight is equivalent to 3500 calories. By making small changes like eliminating 250 calories a day from food and expending 250 calories a day from exercise, you can lose one pound (of mostly fat) per week. You can calculate how much time you need to exercise to burn 250 calories by clicking here. You can calculate your caloric needs by clicking here, and then subtract 250 from that number.

9. Eating slowly can lead to weight loss

Did you ever notice that thin people take an awfully long time to eat their food? Eating slowly is one method that can help take off pounds. That's because from the time you begin eating it takes the brain 20 minutes to start signaling feelings of fullness. Fast eaters often eat beyond their true level of fullness before the 20 minute signal has had a chance to set in. The amount of calories consumed before you begin to feel full can vary significantly depending on how quickly you eat. So slow down, take smaller bites and enjoy and savor every tasty morsel.

10. Weight loss through eating less fat - but do it wisely

We've known for some time that limiting high fat foods in the diet can be helpful with weight loss. That's because fats pack in 9 calories per gram compared to only 4 calories per gram from proteins or carbohydrates. To many, the message to limit fats implied an endorsement to eat unlimited amounts of fat-free products. Just to clarify, fat-free foods have calories too. In some cases fat-free foods have as many calories as their fat laden counterparts. If you eat more calories than your body uses, you will gain weight. Eating less fat will help you to lose weight. Eating less fat and replacing it with excessive amounts of fat-free products will not.