Exercise vs. Diet in Weight Loss

Christina J. Paez and Len Kravitz, Ph.D.

Article Reviewed: Ross, R., Freeman, J. A., & Janssen, I. (2000). Exercise alone is an effective strategy for reducing obesity and related comorbidities. Exercise and Sport Science Reviews, Vol. 28, No. 4, pp. 165-170.

INTRODUCTION

It is estimated that 55% of the adult population in the United States are either obese or overweight (National Institutes of Health, National Heart Lung, and Blood Institute, 1998). Obesity substantially increases an individual’s risk of suffering from chronic diseases such as hypertension, coronary artery disease, and diabetes. Those with excess fat in the abdominal area are at increased health risk (National Institutes of Health, National Heart Lung, and Blood Institute). In an attempt to define the role of exercise in the treatment and prevention of obesity, the American College of Sports Medicine (ACSM) held a scientific roundtable to address this subject. Following the meeting, several consensus statements regarding physical activity and public health were released. Two statements are of particular interest to the applied exercise professional. The first statement declares that the addition of exercise to a diet with restricted caloric intake promotes fat loss, while maintaining fat free mass. The second statement claims that physical activity, without caloric restriction, minimally if at all affects fat loss. The statements suggest that to optimize weight loss, a combination of diet and exercise is best, and that exercise alone will not suffice. Although it is well established that a regimen of diet and exercise is the best way to control body weight, a recent review by Ross, Freeman, and Janssen (2000) challenges ACSM’s statement that exercise alone is not an effective method of weight loss. This review suggests that the studies this statement was based upon do not effectively compare caloric restricting programs to increased energy expenditure programs. They conclude that if these factors were equal, exercise alone can be as effective as caloric restriction for weight loss. The purpose of this article is to present Ross et al.’s argument contrasting the ACSM consensus statement.

EXERCISE VS. CALORIC RESTRICTION

In their review, Ross et al. (2000) report that few randomized control trials equally compare diet only to exercise only weight loss programs. For example, in a twelve-week study, Hagan, Wong, and Whittam (1986) compared the amount of weight lost through diet only to the amount of weight lost through an exercise program. The obese women and men in the diet only group (n=24) that reduced their caloric intake lost 5.5 kg and 8.4 kg, respectively. To achieve this degree of weight loss, women decreased their average caloric intake by 945 kilocalories a day while the men decreased their average intake by 1705 kilocalories a day. The exercise only group (n = 24 obese men and women), performed a 30-minute walk/jog program 5 days/week. On average, the women expended 190 kilocalories per session while the men expended an average of 255 kilocalories per session, which resulted in a total weight loss of .6 kg and .3 kg for women and men, respectively. The women in the diet only program decreased their body fat from 35% to 29%, where as the women doing exercise only went from 35% to 33% body fat. Additionally, the men in the diet only group decreased body fat from 26% to 21% where as the exercise only group experienced no change in their body fat. This study clearly illustrates that weight loss through diet only was not equated to energy expenditure through exercise only. Therefore, equal amounts of weight loss should not be expected.

In contrast, Sopko et al. (1985) in a twelve-week study, with obese men, reported that when the negative energy balance created by diet only and exercise only are equal, the two treatments produce similar results. The participants in the diet only group (n=10) experienced a weight loss of 6.1kg by restricting their caloric intake 500 kcal/day. The exercise only group (n=6) lost 6.2 kg by performing a treadmill walking program in which they expended 500 kcal/day. The men in the diet only group went from a body fat of 31.4% to 25%, where as the exercise only group went from 26.7% to 19%. These results show that equivalent amounts of weight loss can be obtained when the energy expenditure from exercise is similar to the amount of calories restricted through diet. This is contrary to the results of Hagan et. al., as well as the ACSM consensus statement that exercise without caloric restriction minimally affects weight loss. Table 1 summarizes some diet versus exercise weight management studies, further validating when energy expenditure is matched, weight loss is similar.

   

  EXERCISE WITHOUT WEIGHT LOSS: THE HEALTH CONNECTION

Excess fat in the abdominal area independently increases an individual’s risk of insulin resistance and high blood lipids. This distribution of body fat is also a strong predictor of cardiovascular disease (Grundy et al., 1999, National Institutes of Health, National Heart Lung, and Blood Institute, 1998). It has been shown that weight management programs resulting in a loss of total body fat also reduce a person’s amount of abdominal fat. This loss of abdominal fat is associated with a decreased risk of cardiovascular disease. However, it has been shown that exercising individuals, who do not experience any overall weight loss still decrease their risk of suffering from cardiovascular disease (Ross & Janssen, 1999). The current research suggests that exercise without weight loss is actually linked to reductions in visceral fat (Ross & Janssen 1999). In two similar studies, Ross et al. (2000) and Sopko et al. (1985) showed that exercisers who did not lose weight experienced improved insulin sensitivity and an increase in their ‘helpful’ HDL cholesterol. These findings are important because in the event that weight loss is not achieved, a person who is at increased risk of coronary artery disease (CAD), or its comorbid conditions (i.e., high blood pressure, glucose intolerance, insulin resistance), still benefits from regular aerobic exercise participation.

PRACTICAL APPLICATIONS AND RECOMMENDATIONS

The applications from this review article are consequential to the personal trainer and fitness professional for two important reasons. It is well established that exercise and diet modification is the best method for weight loss. However, Ross and colleagues and Sopko and associates also show the efficacy and worth of exercise only programs for promoting weight loss (in overweight and obese populations). Also, from a health perspective it is quite meaningful to emphasize that aerobic exercise independently decreases the risk of CAD and related comobidites. For health benefits, Ross et al. (2000) confirm established recommendations of regular, moderate-intensity physical activity, such as brisk walking, for 30 to 60 minutes on most days of the week. The also suggest that “substantial reductions in obesity and related comorbid conditions will result when daily exercise is performed at a moderate intensity for 45 to 60 minutes a day without deceasing caloric intake.” However, since most of this health benefits research has been done in predominantly male populations, more research is needed with overweight and obese female populations to validate these benefits in women.

References:

Grundy, S.M., G. Blackburn, M. Higgins, R. Lauer, M. Perri, D. Ryan. Roundtable Consensus Statement: Physical activity in the prevention and treatment of obesity and its comorbidities. Med. Sci. Sports Exerc. 31: S502-S508, 1999.

Hagan, R.D., S.J. Upton, L. Wong, and J. Whittam. The effects of aerobic conditioning and/or caloric restriction in overweight men and women. Med. Sci. Sports Exerc. 18:87-94, 1986.

National Institutes of Health, National Heart, Lung, and Blood Institute. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report. Obes. Res. 6(Suppl 2), 1998.

Pate, R.R., M. Pratt, S.N. Blair, W.L. Haskell, C.A. Macera, C. Bouchard, D. Buchner, W. Ettinger, G.W. Heath, A.C. King, et al. Physical activity and public health. A recommendation for the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA. 273:402-407, 1995.

Ross, R., D. Dagnone, P.J.H. Jones, H. Smith, A. Paddags, R. Hudson and I. Janssen. Reduction in obesity and related comorbid conditions after diet-induced weight loss or exercise-induced weight loss in men: A randomized controlled trial. Ann. Intern. Med. 133:92-103, 2000

Ross, R., and I. Janssen. Is abdominal fat preferentially reduced in response to exercise-induced weight loss? Med. Sci. Sports Exerc. 31: S568-S572, 1999.

Ross, R., J.A. Freeman, and I. Janssen. Exercise alone is an effective strategy for reducing obesity and related comorbidities. Exerc. Sport Sci. Rev. 28: 165-170, 2000.

Sopko, G., A. Leon, D. Jacobs, N. Foster, J. Moy, K. Kuba, J. Anderson, D. Casal, C. McNally, and I. Frantz. The effects of exercise and weight loss and plasma lipids in young obese men. Metabolism. 34:227-236, 1985.

Stefanick, M.L., S. Mackey, M. Sheehan, N. Ellsworth, W.L. Haskell, and P.D. Wood. Effects of diet and exercise in men and postmenopausal women with low levels of HDL cholesterol and high levels of low-density lipoprotein (LDL) cholesterol. N. Engl. J. Med. 339:12-20, 1998

Exercise for Belly fat

With all the takeaway food we eat, only the lucky few avoid some sort of flabby gut without doing some form of exercise for belly fat. Two of the best types are planks and crunches. Before you begin on either, remember pregnant women shouldnt complete these exercises. Likewise, if you have got back problems, doing crunches on the hard surface could aggravate those difficulties, so dont accomplish that. As always, loosen up before and stretch out afterward. Never stretch out cold muscles.
 

Boards
   For the stomach plank, lie on to the floor face down together with your weight on the forearms and toes. Straighten your body, as rigid and straight as it can be, from neck to ankles for the 30-second holds (use the actual old one-Mississippi, two-Mississippi means for counting the seconds). Do three sets of 20 (or however many you can do to begin with and progress up to three sets). Thirty-second holds are a starting point. Gradually increase the hold time as you grow more used to the exercise. In the event this becomes also easy, do the exercise having a stability ball under your toes. The more you are doing the more belly fat you will burn off.

  Another intense exercise for belly fat is the aspect plank, start from the basic plank position (weight on toes and elbows), and roll one side, placing all your unwanted weight on one forearm as well as placing your upper foot in your lower foot (the pounds is now privately of your foot), as well as extend your totally free arm straight way up. Hold that for 30 seconds, after which it reverse, holding that for 30 seconds. This exercise can even be done with immediately arms, weight resting on the palm of the actual hand. Thats a little more challenging balance-wise, but like whatever else, it gets less difficult with practice. Yet again, the goal can be three sets regarding twenty.

Crunches
   For a more old-school exercise for belly fat, do some crunches. Lie on your back together with your knees bent as well as your feet flat on to the floor. Position your toes as wide because your hips, hands behind your mind, and tuck fingers behind your ear. Use your abdominal (not your hands) to lift your mind, neck and back off the flooring. Dont pull your mind forward with the hands. Keep your face off your chest. Hold that position until it starts to burn, after which it count to 5 before lowering. Do three sets of however many you can do, and keep intending until failure (i. e., until you find it difficult to do anymore).

   An oblique meltdown adds rotating slightly together with your shoulders, moving certainly one of your elbows toward and the second knee, while undertaking the crunches. To increase the intensity of one's stomach fat exercise, add a stability ball to the mix.

  Stomach fat exercise should participate in your daily program. It not only allows you to look better, it remedies back pain a result of extra weight upon on weak muscles in your stomach and back. You dont receive as tired because you arent hauling around extra belly fat. Working your abdominal helps your position and eliminates anxiety. All in many, you couldnt do yourself a more impressive favor.