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Weight Control and the Arborist

By John Amtmann and Brian Schwarzkoph

Arborists may benefit from maintaining a healthy body fat percentage not only because of the health effects, but also because a long day of working in the trees can be less stressful if our strength to body weight ratio is more favorable. A great way to determine whether your weight is at a healthy level is to have your body fat percentage calculated by a certified health/fitness professional. A common method health/fitness professionals use is to measure skin-fold thickness at specific sites on the body, and, using these measurements, total body fat percentage can be calculated. Most Americans have an issue with having too much fat and, though arborists are more physically active than your average American, we have our fair share of professionals carrying extra pounds. If our body fat percentage is too high, it can impede our overall efficiency when working in the trees, can cause us to become fatigued earlier in the work day and increase the chance for injuries/accidents, and can reduce our abilities to self-rescue. Men should be between 5-13% body fat and women should be between 12-22% body fat for optimal performance and for maintaining health. Weight loss should be dictated by nothing more than body composition, and you can usually get your body composition measured at any local gym or YMCA.

If you are above the recommended range, then you can determine your ideal body weight by doing a few simple calculations:

Total Body Fat (TBF) = body weight x % body fat/100
Fat Free Body Weight (FFW) = body weight – total body fat
Ideal Fraction (IF) = (100 – ideal body fat %)/100
Ideal Body Weight (IBW) = Fat Free Body Weight/Ideal Fraction

If Sheila, with a current body weight of 150 pounds and body composition of 25% fat, wanted 20% body fat as her goal, her ideal body weight would be calculated as follows:

TBF 37.5 = 150 x 25/100
FFBW 112.5 = 150 – 37.5
IF .80 = (100 – 20)/100
IBW 140.6 = 112.5 / .80

Another common way to determine whether or not we are at a healthy weight is body mass index. The body mass index, or BMI, is a calculation that relates height to body weight and allows us to categorize ourselves in one of four categories: underweight, normal, overweight, or obese. BMI is calculated by taking body weight in kilograms divided by height in meters squared, Kg/m2. This equation, however, does not distinguish between where the weight is coming from, whether it is muscle, fat, or bone. With this being said, the BMI formula is not always accurate for athletes or people with low body fat and high muscle mass. For the normal person it can justly serve as an accurate representation of body composition. What category do you fall under? The American College of Sports Medicine lists Underweight as less than 18.5, normal as 18.5-24.9, overweight as 25.0-29.9, and obese as 30.0 and above. Once a BMI of 30 or above is reached there is an increased risk of hypertension, high cholesterol levels, cardiovascular disease, and mortality. Try calculating your own BMI, or visit the following website (http://www.eatright.org/bmi/) and see where you stand. Don’t worry if your number puts you in the overweight or obese category. Consider it a starting point to become a more healthy individual. The first step to losing that unwanted body fat is educating yourself on the foods that are beneficial and will fuel your body during a weight loss program.



BMI (kg/m2)


Less than 18.5






Above 30.0

ACSM’s Guidelines for Exercise Testing and Prescription

Following the U.S.D.A. Food Guide Pyramid is an excellent way to ensure that you are taking in calories that provide nutrients that every industrial athlete needs. We also recommend a multi-vitamin and mineral supplement.

Notice that most of your calories should be coming from breads, cereals, rice and pasta, fruits and vegetables. We recommend nutritional, natural and/or whole grain products. For example, eat seven grain cereal instead of Captain Crunch, multigrain oatmeal instead of Honey Combs, an apple instead of apple pie. This doesn’t mean you can’t enjoy a brownie, a piece of pie, a juicy steak, or whatever. You can, you just can’t be a glutton about it.

Energy balance is a term used to describe energy intake or the calories consumed in the diet, and energy expenditure or the calories burned in the course of daily activities. If energy intake exceeds energy expenditure, the excess will be stored as fat. Weight loss occurs whenever energy expenditure exceeds energy intake. One pound of fat has about 3,500 calories, so if you expend 500 cal/day below your caloric needs (i.e. a 500 calorie “deficit”), it will take 7 days to lose one pound of fat. You can create a caloric deficit by reducing your caloric intake, increasing your energy expenditure through additional exercise, or through a combination of the two. Proper weight loss should always combine reductions in caloric intake and exercise. If weight loss occurs at a rate greater than two pounds per week, it’s likely that some of this weight reduction will be the result of lost muscle tissue and/or water, which is undesirable. So, be patient and be smart about how you choose to lose weight. There are some subtleties that must be addressed before you decide to eat less and exercise more.

A sound plan for fat loss includes the following recommendations:

1. EAT! Consuming a reasonable number of calories by following the Food Guide Pyramid will ensure a balanced assortment of vitamins and minerals by including foods from all food groups. You should only reduce energy intake by about 250 cal below daily energy expenditure. This is equivalent to about one slice of pizza. More drastic reductions in caloric intake may cause negative consequences such as metabolizing muscle instead of fat (which you DO NOT want), and severely lowering resting metabolic rate – the chief source of caloric expenditure at rest. Eat a healthy breakfast, lunch and dinner, with healthy snacks in between to reduce the chance that you’ll binge.

2. EXERCISE! Available evidence indicates that excess weight gain often parallels reduced physical activity rather than from increased caloric intake. Strength training is an important aspect of weight control since muscle mass has a direct effect on resting metabolic rate. This is one good reason why you should not drastically reduce caloric intake; it will impede your body’s ability to effectively recover from your strength workouts.

3. The plan should offer a balanced assortment of vitamins and minerals by including a variety of foods from all food groups.

4. No unproven or spurious weight-loss aids should accompany any sound eating plan. Meaningful changes in body fat take time — at least 4 weeks. A sound diet should not promise dramatic, rapid weight loss, but rather encourage permanent, realistic lifestyle changes that will decrease body fat gradually. To lose fat, about 1 pound per week should be the goal for permanent fat loss.

5. “Diets” to avoid, include:

Low carbohydrate diets
High protein diets
Low protein diets
Low fat diets
Starvation diets

In a sense, you will not be “dieting”, just making healthy eating choices. We need to keep in mind the importance of strength training. Don’t get caught up in the misperception that aerobic exercise is the only method for controlling fat. Strength training will lead to improvements in muscle mass. Muscle is the furnace that burns fat, even during rest. Extreme weight loss measures, on the other hand, actually cause a decrease in muscle mass. Remember, adding muscle will increase resting metabolic rate, which will make fat loss much easier and more efficient than endless aerobic exercise sessions.

For weight gain in the form of muscle mass, a combination of diet and strength training is key; however, genetic predisposition, somatotype, and compliance will determine your progress. Extra calories usually must be consumed for muscle growth to occur, and about 2,500 total extra calories need to be consumed to facilitate a 1 pound increase in muscle tissue. Thus, 350 to 700 kcal above daily requirements would supply the calories needed to support a 1 – 2 pound weekly gain in lean tissue as well as the energy requirements of the training. More than 1 – 2 pound weekly gains will probably be accompanied by significant increases in fat. If the weight gain is less than about 2 pounds per week and is the result of a well-planned strength training program, then it will probably be in the form of muscle tissue.

A sound plan for weight gain includes:

Increased portion sizes.
Increased eating frequency by adding mid morning, mid afternoon, and night time snacks.
The extra calories should be from healthy, nutritional sources.
Strength Training! Follow the guidelines in previous articles.


Some practical examples:


Bob’s total body weight was 180 pounds, and his body composition was calculated to be 20% body fat through skin-fold measurements.

TBF 36 = 180 x 20/100
FFBW 144 = 180 – 36
IF (for 15% body fat) .85 = (100 – 15)/100
IBW 169.4 = 144 / .85
Pounds to lose = 10.4

So, Bob can stand to lose about 10 pounds. Using the recommendations above, he could take 10 weeks to lose this weight in fat. If all the weight lost was fat, his body fat percentage should decrease to 15%.



Sue’s body fat was 23%, and her total body weight was 145 pounds.

TBF 33.35 = 145 x 23/100
FFBW 112 = 145 – 33
IF (for 18% body fat) .82 = (100 – 18)/100
IBW 136.6 = 112/.82
Pounds to lose = 8.4

If Sue took 8-9 weeks to lose this weight in fat using the recommendations above, then her body fat percentage will decrease to about 18%.

Gaining, losing or maintaining body weight is little more than a matter of arithmetic. If more calories are consumed than expended, weight is gained. If more calories are expended than consumed, weight is lost. If calories expended and consumed are equal, weight will not change.


John Amtmann is a professor of Applied Health Science program at Montana Tech in Butte, Mont. He works as an arborist during the summer, and can be reached via e-mail at jamtmann@mtech.edu. Quarterback for the Montana Tech Orediggers, Brian Schwarzkoph is an Applied Health Science student at Montana Tech, and is a tree worker in his spare time. He can be reached via e-mail at BWSchwarzkoph@mtech.edu.




American College of Sports Medicine. 2010. ACSM’s Guidelines for Exercise Testing and Prescription. Eighth Edition. Philadelphia: Lippincott Williams & Wilkins.
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Sattler, T., Mullen, J. 1995. Exercise and Weight Control. In The Fitness Handbook, Second Edition. Peterson, J., Bryant, C., Editors. Champaign, IL: Sagamore Publishing. Pp 229-244.
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