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Additional Weight Loss Discussion: What You Need to Know About Weight Loss  

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Reviewed for medical accuracy by:

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Robert Egbers

Kestrson S., M.D.


UM Medical School


Part 1: Introduction and Diet Basics


An estimated 40% of Americans will set a New Year's resolution to lose weight this year.  Unfortunately, after just one year as many as 95% of these people will be at their original weight or higher.  The hurdles are numerous: time constraints, over-availability of unhealthy foods, peer pressure to live an unhealthy lifestyle, and so on.  I know these hurdles well, in December of 2004 at 230 lbs I made the decision to lose about 30 lbs during the following months.  Two years later I am still 30 lbs lighter.  In this article I hope to educate you and give you some tips to help you reach and maintain your weight loss goals as I have.


Energy Balance

First, I want to explain a few basics.  Nature is governed by laws that we cannot escape like gravity.  The second law of thermodynamics is one of these laws and is especially important in our fight to lose weight.  It says that energy is neither created nor destroyed, it just changes forms.  This law leads us to the most basic equation of weight loss: Energy Consumed (Calories from carbohydrates, fats or protein) = Energy Burned (Calories) + Energy Stored (Calories in fat or glycogen).  If you earned your middle school diploma, you can see that the energy you consume in the form of food that isn't burned is stored. 


Unfortunately, most of this extra energy is converted to fat and stored.  An intake of only a few calories in excess of those burned over time can accumulate as extra pounds.  Your body stores energy as fat because it is the most efficient form of energy storage.  Look at a label of food, each gram of carbohydrates has 4.5 Calories, each gram of protein likewise contains about 4.5 Calories.  In contrast, a gram of fat has 9 Calories.  Strike one against fats.


Calories consumed can be burned by three different systems, basal metabolic rate, the thermal effect of food or by activity.  Your basal metabolic rate (BMR), approximately 70% of your total energy expenditure, is the energy required to supply your organs with enough energy to conduct their vital functions.  BMR can be increased by increasing lean body mass (via resistance training) or with increased cardiovascular exercise.  Stimulants such as caffeine or hormones like those produced by the thyroid gland also increase your BMR.  BMR is naturally decreased by age or a restricted calorie diet.


The thermic effect of food or TEF is the energy expended by your body in processing the calories you eat.  This component of energy expenditure is actually controlled by the types of food that you eat.  TEF accounts for approximately 10% of total calories but is higher for proteins, and high fiber fruits and vegetables.  Fats have a low TEF and are more efficiently absorbed and processed.  Strike two against fats.


The remaining 20% of energy expenditure can be attributed to active energy expenditure.  Along with increasing your basal metabolic rate, exercising will increase the calories burned directly through active energy expenditure.


This isn't the whole story though.


Not all calories are created equal.

The sum of the calories of proteins, carbohydrates and fats you eat needs to be considered in determining your daily caloric intake as just described by the 2nd law of thermodynamics.  But not all calories have the same effect once inside your body.  To complicate things, research has shown that diets with a higher percent of fat calories than carbohydrate calories produce a greater loss in weight [1], protein and total calories were held constant amongst the study groups.  So although a gram of fat contains more calories than does a gram of carbohydrates, your body responds differently to a calorie of fat than a calorie of carbohydrates.  One reason for this difference could be the insulin response to sugar hitting the blood stream.  So fat steps up with two strikes and hits a home run?  Yes, as long as you still restrict your total caloric intake to less than the energy spent.  In addition omega-3 and omega-6 fatty acids as well as some fat soluble vitamins are essential and must be ingested via fat in food or nutritional supplements.  I feel that it is important to mention here that consuming too much saturated and trans-fat can be detrimental to your cardiovascular health. 


Now, lets look at carbohydrates.  Maybe you have heard about some of the newer diets on the market that focus on the glycemic index of food.  The glycemic index is a rating given to a food based on how quickly glucose (sugar) appears in the blood stream after consuming the food.  Carbohydrates are made up of small units of glucose called monomers.  Carbohydrate foods with a low glycemic index such as high fiber fruits take your body longer to digest and absorb the sugar into the blood. 


Science does support the preference for low glycemic index foods not only for diabetics, but for people trying to lose weight.  As sugars hit the blood stream, it stimulates the pancreas to secrete insulin.  Insulin stimulates the cells of your body to uptake and store glucose.  And insulin causes a metabolic shift leading to an increase in fat stores in the liver and fat cells (adapocytes).  High glycemic index foods leading to increased fat stores can be counter productive to weight loss efforts.

I found a good listing of low glycemic index foods at www.mendosa.com/common_foods.htm.  You should be starting to see how the composition of where you get your calories can effect your weight loss.


Where does weight loss come from?

During the weight loss process your body's energy stores (fat, proteins and glycogen) will be mobilized and burned.  Ideally all these calories will be from fat reserves, too bad your body doesn't completely cooperate. 


Glycogen is one of the ways your body stores sugar (glucose) in a form that is readily accessible in organs that require it's constant use such as the liver and muscles.  Since glycogen is such a readily accessible form of energy and it requires a lot of water to store it, the quick weight loss associated with many diets can be attributed to the loss of this glycogen.  Burning all your glycogen stores and not replenishing them from a carbohydrate source can lead to problems such as early muscle fatigue.


Proteins are another reserve energy source that we want to protect since they constitute the lean body mass that strengthens your basal metabolic rate.  Conventional wisdom suggests that as much as a 30% [2] loss of lean body mass is an unavoidable side effect of fat loss. 


However, Diebert et al [3] showed that a high protein diet with or without exercise can be protective of muscle while achieving a significant reduction in weight.  In the study, the subjects replaced two meals per day by a protein preparation (Almaseds) for the first 6 weeks, followed by the replacement of one daily meal for 18 weeks. For the latter time interval, the dietary intake of fat was limited to 60 g/day.  This diet contained about 1000 calories /day for women and 1200 calories /day for men in the first 6 weeks  The final 18 weeks the diet wasn't to exceed 1500 calories /day for women and 1700 calories /day for men.  This translates to at a minimum of 26% of daily calories attributable to protein. 


Other research suggests that a dietary protein composition of between 25% and 30% or strength training may be protective of lean mass during weight loss, although authors suggest more research needs to be conducted in the area [4].  This review also found that when a casein protein was used, gains in lean mass were doubled (+4.1 vs +2.0kg) with a greater reduction in fat mass (–7.0 vs –4.2kg) compared with a whey protein supplementation.  Your take away message from all of this is to include a resistance training regimen along with a minimum of 26% daily calories due to protein.


Evolution isn't on your side

Working against us, nature has evolved efficient feedback systems.  They work to change the energy you consume and the energy you burn to help your body  maintain its “set-point” weight.  This genetically controlled system is counter productive to your weight loss efforts.  For example, when you begin to lose fat stores, hormones like leptin (made by your fat cells) decrease, signaling your body to consume more calories and expend fewer calories. 


Likewise, hormones produced by the digestive system are involved in the regulation of hunger.  When the stomach is empty, ghrelin is released by the lining of the stomach which increases the sensation of hunger.  In response to eating certain foods such as fats, hormones like cholecystokinin are released from your digestive system and produce the sensation of fullness.  There is little we can do to modify these evolutionary safe guard mechanisms, but you should be aware of the difficulties they present to your weight loss efforts.


More discussion to come on the role of exercise in weight loss.


Part 2: Exercise Basics


Up to this point, we have discussed primarily the Energy Consumption part of the energy balance equation (Energy Consumed = Energy Spent + Energy Stored).  Now lets look more at the energy expenditure part.  Before beginning this discussion, I want to say that you must consult with your physician before taking on any increase in activity level to ensure you wont be doing more harm than good. 


Adding exercise to your weight loss program will help you burn more calories both directly at the gym and indirectly by an increase in your metabolic rate throughout the day.  The focus of your program should be aerobic exercise because of its efficiency in burning large quantities of calories.  To compliment the aerobic exercise, resistance training should be used to maintain your lean body mass and basil metabolic rate during weight loss.


The aerobic and anaerobic energy systems are different.  The aerobic system is utilized during moderate intensity exercise over long periods of time.  This system is characterized by the conversion of oxygen to water with the production of energy. The anaerobic system on the other hand is characterized by the conversion of pyruvate to lactic acid during energy production.  The anaerobic system is utilized during short intense exercises and when the aerobic system is unable to meet the energy demands of muscle cells.  Once the aerobic system's capabilities are exceeded and the anaerobic system is activated, your muscles are using a large quantity of energy in the form of adenosine triphosphate (ATP), which is the energy currency of all cells.  This large quantity of ATP is responsible for acidosis and in turn muscle fatigue during anaerobic exertion.  So you want to keep your body using primarily the aerobic energy system to minimize the early onset of fatigue.


Using heart rate measurements is a good way to estimate the intensity of your work out and what systems your energy is coming from.  At any point during your work out you can estimate your heart rate by counting the number of pulses per minute in an artery.  Two easily found arteries are the radial artery in the wrist and the carotid artery in the neck. 


First, you need to calculate your max heart rate as follows: HRmax = 220 – Age.  Then use the following chart to find out which zone you are training in.  For example, I am 27 years old, so my Hrmax is 193  pulses per minute and to be training in the Aerobic Zone, I would need my heart rate fall between 135 and 154 beats per minute.


Target Zone

% of HRmax

% Cals from Fat

Healthy Heart Zone (Warm up)



Fitness Zone (Fat Burning)



Aerobic Zone (Endurance Training)



Anaerobic Zone (Performance Training)



Red Line (Maximum Effort)




With increasing % HRmax, you increase the total calories burned per minute.  You can also see that the lower the % HRmax, the higher the % Calories burned from fat.  As named, the “Anaerobic Zone” (80-90% HRmax) is where anaerobic metabolism starts to initiate and you may encounter premature fatigue.


Although a greater percent of calories burned are from fat in the “Fitness Zone” than in the “Aerobic Zone,” you will burn a greater number of total calories per minute in the “Aerobic Zone.”  These extra calories would have otherwise been converted to fat.  Therefore, exercising in a higher % HRmax zone will maximize your weight lost per minute.  Don't forget though that you are not only exercising for one minute, and if you exercise in the “Anaerobic Zone” you will fatigue before appreciable calories can be burned.  Research has shown that sustained increased metabolic rate after exercise increases with intensity and duration of exercise [5].


To develop an optimal exercise regimen for yourself, you are going to have to take the information presented here and adapt it to your own exercise tolerance, what exercises you like, and what works for you logistically.  Again, if you are just starting out with exercise or if you have complicating health conditions you must consult with your doctor before engaging in any exercise program.


Part 3: Quick Work Out Tips


Start Your Exercise Program Slowly

If you haven't worked out in a while it is important to start slowly and stretch before each work out.  If you jump back into working out too quick or without stretching, you increase your risk of injury.  This will destroy your motivation and derail your weight loss effort, so start slowly.  You should target 3 work outs spread out over the week at first then gradually increase frequency.


Resistance Training

After you are done stretching (Don't forget to do upper and lower body), you are ready to start exercising.  Start with your resistance training, it burns off extra short term energy stores and helps protect your lean mass during fat loss.  Alternate upper body resistance training days with lower body resistance training days.  A good starter upper body routine is bench press, shoulder press, pull-ups, curls, and arm raises.  For the legs, start with squats, lunges, curls, extensions, and standing calf raises.


Use a weight that you can safely lift for 3 sets of 8-15 repetitions using negative resistance.  Negative resistance is when you provide extra force on the way back down (count to 3 while you let gravity return the weight to the starting position).  This method promotes better muscle gains and allows you to use a lighter, safer weight.  You should start on resistance machines instead of free weights until you become comfortable with the motions and weights for each exercise.


Aerobic Training

The most efficient way to lose weight and the whole focus of your work out should be aerobic exercise.  At first, your target heart rate range should be between 50-60% HRmax (HRmax is 220 – your age) for at least 3 or 4 days per week.  I suggest using the elliptical machine and swimming because they are both low impact.  Both do put different stresses on the body though, so be conscious of your personal limitations.


Once you are already properly conditioned, continue to focus on aerobic exercise but don't forget about resistance training.  You should try to work up to at least 5 sessions per week with each lasting longer than 30 minutes [6] with a target heart rate range approximately 70-80% of HRmax. 


Don't Over Spot Train

Don't be fooled by the old tale that working out one area burns more fat specifically in that area.  For instance, just doing sit-ups isn't going to burn fat specifically from your stomach.  Actually you are better off doing something that burns more calories during that time like running.  Sit-ups do make your abdominal muscles larger, which can help them stand out if a little bit of fat surrounds your waist.


When to Exercise

Often people say that working out in the morning is best because you can maximize the benefit of post exercise metabolism increase.  More importantly though, you need to choose a time to work out when you will consistently go.  You don't lose any weight just planning on working out in the morning and sleeping through your alarm because you are a night owl. 


That being said, many people will find that working out before work will help make exercise a priority in their life.  By working out before work or class, you will be less likely to be sidetracked and justify skipping.  Additionally, getting to the gym in the morning is more time efficient because you can avoid the after-work rush.  Some people get an added benefit of feeling a sense of accomplishment by working out while other people are asleep.


Optimize What You Already Do

This is where you get to use some personal creativity to burn calories.  Think of the things that you do on a regular basis and try to turn them into an opportunity to burn some additional calories.  For instance you can park far from the entrance to work and walk, ride your bike to work, or walk up the stairs instead of the elevator.  My personal favorite was using 5 lb ankle weights during work.  It turned normal walking into an added calorie burning exercise.  See what you can think of and try it out.


Quick Diet Tips


Your Diet

You should have approximately 26% of your calories from protein to protect against muscle loss (a good total calorie target is 1,500 calories /day for women and 1,700 calories /day for men).  The rest should be a balance of carbohydrates (remember to maximize low glycemic index carbohydrates) and fats at a ratio of approximately 2:1.  Fat is not as scary as once thought and is an essential part of your diet.  At the same time, you should try to minimize trans-fatty acids found in foods containing “partially hydrogenated oils” due to their detrimental cardiovascular effects.  For the same reason, minimize consumption of saturated fats found in butter, lard, coconut oil, cottonseed oil, dairy products and meat.


Drink Plenty of Water

One study found that drinking between 6-7 8oz glasses of water can actually help burn as much as 5 pounds per year [7].  I contend that drinking water will actually burn more calories as drinking water will help you forgo drinking high calorie, high glycemic index drinks.


Avoid Cheat Days

Don't be fooled into thinking that it is good to have a cheat day.  You are just hurting your cause and tempting yourself with the foods you are trying to avoid.


Quick Mental Tips


Avoid Your Vices

All types of alcohol have have calories, no exceptions.  If you need proof, pardon the pun, read the label.  For instance Miller Lite, a low calorie drink, has 96 calories per bottle (Guiness has 210 calories per pint).  If you go out and have 6 beers, that is 576 calories approximately 1/3 of your daily calorie goal.  This doesn't even include the high calorie diner food and munchies you are likely to encounter after the bar.  In my opinion alcohol is not worth the allocation of valuable calories.


Make it Competitive

It is so easy to revert back to your old diet and lifestyle after the novelty of your effort wears off.  Since you are probably not the only person you know trying to lose weight this year, maybe start weight loss competition.  This can be for personal pride or some other prize, that your group can award the weight loss winner.  A competition can help you build a support network, increase your accountability, and provide the little extra motivation that may help you succeed.


Document Your Efforts

This is quite challenging, but amazingly valuable.  You can use a spreadsheet program or just a small notebook.  The point is to document all the calories that you consume for accountability.  It is so easy to nibble a chip here and a candy there, but by writing down absolutely everything, you see how fast these calories add up.  Writing down every calorie consumed keeps you honest and the pounds flying off. 


The following is a good website for how many calories burned doing common activities: http://www.primusweb.com/fitnesspartner/jumpsite/calculat.htm.  You can subtract the sum of the  calories you burn each day from the calories you consume each day.  This way you can get a rough estimate with how you are doing and project if you will reach your goals.  Remember that there are 3,500 Calories in a pound of fat.



Losing fat isn't easy or else everyone would be thin. Be realistic with personal expectations of weight loss, you have probably spent a long time putting the weight on, it isn't coming off overnight. 


The suggestions in this article are just a starting point to lose weight.  To live a truly healthy life, you need to permanently adopt healthy lifestyle changes and adjust your practices according to the most current reliable research on the subject.   I wish you luck in your weight loss journey. 



1. Young CM, Scanlan SS, Im HS, Lutwak L. Effect of body composition and other parameters in obese young men of carbohydrate level of reduction diet. Am J Clin Nutr 1971;24:290–6.


2.Ballor DL, Poehlman ET. Exercise-training enhances fat-free mass preservation during diet-induced weight loss: a meta-analytical finding. Int J Obes Relat Metab Disord 1994; 18: 35–40.


3. P Deibert, D Ko¨nig, A Schmidt-Trucksaess, KS Zaenker, I Frey, U Landmann and A Berg.  Weight loss without losing muscle mass in pre-obese and obese subjects induced by a high-soy-protein diet. International Journal of Obesity (2004) 28, 1349–1352


4.Petra Stiegler and Adam Cunliffe.   The Role of Diet and Exercise for the Maintenance of Fat-Free Mass and Resting Metabolic Rate During Weight Loss.  Sports Med 2006; 36 (3): 239-262


5. Elisabet Børsheim and Roald Bahr.  Effect of Exercise Intensity, Duration and Mode on Post-Exercise Oxygen Consumption.  Sports Med 2003; 33 (14): 1037-1060.


6. Jeff S. Volek, Jaci L. VanHeest and Cassandra E. Forsythe.  Diet and Exercise for Weight Loss.  Sports Med 2005; 35 (1): 1-9.


7. Boschmann M. Steiniger J. Hille U. Tank J. Adams F. Sharma AM. Klaus S. Luft FC. Jordan J. Water-Induced Thermogenesis. Journal of Clinical Endocrinology & Metabolism. 88(12):6015-9, 2003 Dec.


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