Health, Diet, Fitness and Weight Loss Blog
The Simply Fit Diet
It’s Your Diet, Stupid
(Diet beats exercise for weight loss)
The scene is familiar, a TV weight-loss
contestant breaks into tears struggling to
complete a daunting physical task.  By
the end of the show, the contestant is fit
and trim.  Viewers take away the
message that exercise is the best way to
lose weight.  But that is not true.

If you exercise regularly but do not lose
weight, it is time to say to yourself, “it’s
your diet, stupid.” A meta-analysis of 493
studies conducted over 25 years says
that diet is almost five times more
effective than exercise for weight loss
(
1).  Dieters lost an average 2.2 pounds
per week, while exercisers lost only .44
pounds (
see figure 1).  Surprisingly, in
the short term, those who combined diet
and exercise lost virtually the same
amount per week as those who dieted
only.  However, after a year, people who
combined diet and exercise maintained
the most weight loss, followed by those
who dieted only, with those who
exercised only coming in last.  Another
study found that neither strength training
nor aerobic training plus dieting offered
a weight-loss benefit over dieting alone
(
2).












Exercise, of course, has health
advantages beyond simple weight loss.  
For example, it helps to prevent
diabetes.  About 12.3% of American
adults over age 20 have diabetes,  37%
have pre-diabetes, and 51% of those
over age 65 have pre-diabetes (
3). The
importance of exercise cannot be
downplayed, but it should not be
overplayed.

At least 75% of the fitness equation is
diet, but that most people spend 75% of
their effort on exercise.  Perhaps
Americans like taking action, plus
advertisers want to sell gym
memberships, workout videos and
exercise gizmos.  The bottom line is that
most people focus too much on exercise
and too little on diet.”

Sometimes people, because of time
constraints or physical challenges,
question whether dieting without
exercise is worthwhile.  For them,
science shows that diet alone can
provide nearly as much benefit as diet
plus exercise.  Combining diet and
exercise gets a gold medal in the fitness
arena, but diet alone brings home a
silver.  The biggest emphasis for those
looking to lose weight should be diet, not
exercise.
A chart comparing weight loss from diet, exercise and both.
Figure 1. Pounds lost per week.
Footnotes:

----------------------

1. Miller, WC; Koceja, DM; and Hamilton, EJ; “A meta-analysis of
the past 25 years of weight loss research using diet, exercise or
diet plus exercise intervention,” International Journal of Obesity  
(1997) 21, 941-947, at Table 4, page 495.
http://www.iub.
edu/~k562/articles/obesity/review%20Miller%201997.pdf see
also, “The aim of the current study was to compare the effects of 6
months of caloric restriction by dietary restriction only or dietary
restriction in combination with exercise, on body composition and
abdominal fat distribution in overweight men and women. Our  
data suggest that when the level of caloric restriction imposed is
precisely matched and carefully controlled, the changes in body
composition and abdominal fat distribution are not further
enhanced by the addition of exercise, rejecting our hypothesis.”
Redman, Leanne, et al, “Effect of Calorie Restriction with or
without Exercise on Body Composition and Fat Distribution,” J
Clin Endocrinol Metab. 2007 Mar; 92(3): 865–872,
http://www.
ncbi.nlm.nih.gov/pmc/articles/PMC2692618/
“Weight loss was associated with reductions in metabolic risk
factors in obese women. The improvement in the metabolic profile
was not enhanced by the addition of aerobic or resistance
exercise. The findings reinforce the importance of diminished
visceral fat in the treatment of insulin resistance.” Janssen, Ian et
al, “Effects of an Energy-Restrictive Diet With or Without Exercise
on Abdominal Fat, Intermuscular Fat, and Metabolic Risk Factors
in Obese Women,” Diabetes Care, March 2002 vol. 25 no. 3 431-
438,
http://care.diabetesjournals.org/content/25/3/431.long        

2. Geliebter, Allan, et al., “Obesity-Related Hormones and
Metabolic Risk Factors: A Randomized Trial of Diet plus Either
Strength or Aerobic Training versus Diet Alone in Overweight
Participants,” Journal of Diabetes and Obesity, 2014 Jul 29; 1(1):
1–7.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4293637/

3. “National Diabetes Statistics Report, 2014,” Centers for  
Disease Control and Prevention,
http://www.cdc.
gov/diabetes/pubs/statsreport14/national-diabetes-report-web.pdf
All original contents copyright 2017.