It can be very difficult to lose weight. (Gaining weight, on the other hand, is quite easy for most people.) Making matters worse, what many individuals do while attempting to shed a few pounds actually ends up working against them in the long run. When one switches from basically eating what he or she wants to extreme dietary restrictions in order to lose weight, in the short term the needle on the scale will indeed move. But the metabolic effect this has on the body can be detrimental to the cause. (For examples of just how bad this phenomenon can get, see this New York Times article about a study done on the "Biggest Loser" class of 2009 and what happened to their bodies afterwards.)
There are always going to be fad diets of the moment: dietary plans claiming to be The Answer. Just follow these steps to the letter and you will be the size you want and have improved health and all your problems will fade away! Oh, how many times have we seen this? How many millions of diet books purchased? And people still all too often gain back what they have lost (and then some) as soon as they can't stomach the plan any longer.
Most experts agree that if you want to lose weight in a sustainable way, the most effective strategy includes both dietary restriction and exercise. And there is evidence that only moderate dietary restriction (rather than severe) coupled with the right amount of moderate-intensity physical activity (PA) is the best way to accomplish this goal.
In a position stand by the American College of Sports Medicine (ACSM), the authors state that "in studies where energy restriction is not severe (i.e., 500-700 kcal), there is evidence that diet combined with PA is associated with significantly greater weight loss compared to diet alone." Contrast this with comparisons between extremely restrictive diets (i.e., 600-1,000 kcal per day) and these diets plus physical activity. In these comparisons, there are no significant differences in outcomes, which could be the result of a negative effect on metabolism.
In the ACSM's meta-analysis, the amount of moderate-intensity PA that yielded the best results in conjunction with moderate dietary restriction was 150-250 minutes per week. This coincides with the current recommendation for PA supported by the U.S. Department of Health and Human Services and the ACSM, which is that all adults get at least 150 minutes of moderate-intensity PA (or 75 minutes of vigorous PA) per week for improved health and reduction of chronic-disease risk. This amounts to doing a 30-minute cardio session 5 days per week. However, the really good news is that it also can be attained through increments as brief as 10 minutes (a 10-minute walk in the morning; a 10-minute walk at noon; and another 10-minute walk in the evening). In other words, as long as you get in at least ten minutes of cardio, then you can count this short bout of exercise toward your weekly total!
And whether we are talking weight loss or overall health and wellness, there is also a "dose response" relationship between exercise and desired outcomes. So, if you want to reduce your chronic-disease risk even further, then walk/jog/cycle a bit more--up to 300 minutes per week rather than 150. And if you need to lose more weight, and wish to do so in less time, then add more minutes of cardio to that weekly PA total.
But again, forget about doing all that exercise if you are also going to starve yourself through extreme dieting. Your results are not likely to significantly improve, and even if they do, the long-lasting metabolic effects will not be worth the tradeoff.
Doesn't it make more sense to figure out a way to trim just 500 calories per day and get in 30 minutes of cardio? Doesn't that sound better than extreme, "yo-yo" dieting??
It's not even a real question, people. Stop the madness today and go with a moderate, sustainable approach to weight loss. Do so for your weight as well as your overall health and wellness.