Now, before you decide, "OK, thanks for the weight loss advice thus far, but I'm not lifting weights!"; just hear me out.
You see, whenever we go about losing weight, we run the very real risk of losing lean mass. Study after study have shown that when we follow a hypocaloric diet plan (that is, when we eat fewer calories than we need to maintain our weight), lean mass is often lost in addition to fat mass.
Even more, higher protein diets (despite what some "experts" espouse) are not a surefire insurance policy for holding on to our muscle mass while losing weight. Grant it, they do help, but we need to do more if we want to better ensure we hold on to our lean mass while dieting.
Interestingly, one thing, and one thing only, may be more (yes more!) effective than high protein for maintaining lean mass while one endures a caloric deficit. This one thing is resistance training.
Kidney Disease May Hold the Clue
It's well known that very low protein diets can lead to muscle wasting in inactive individuals, but what about active individuals?
Some interesting research conducted by Castaneda et al. in 2001 can tell just what happens. Researches wanted to assess what effect resistance training would have on older individuals with renal dysfunction.
For some background info, people with renal dysfunction (i.e. kidney disease) cannot safely metabolize high amounts of protein. Thus, patients with this disease are prescribed very low protein diets. Subjects in this study were only given .6 grams of protein per 1 kilogram of body weight (about .3 grams per pound of body weight). Not only is this amount much lower than the USDA guidelines for protein (which are arguably too low anyway), but this amount is also way, way, way lower than what typical broscience and gym lore proselytizers advocate.
So what happened to these poor souls who endured such a low protein diet?
Well, researches divided subjects into two groups. One wherein subjects did not practice resistance training, and another wherein subjects participated in resistance training 3x per week. Unsurprisingly, the non-resistance trained group lost muscle mass (even though subjects were not actually trying to lose weight). However, very surprisingly, the group that did participate in resistance training maintained and even gained muscle mass and strength (despite the fact that subjects were consuming relatively low amounts of protein).
What can the results of this study tell us?
That resistance training (not protein per se) is going to be a perhaps more reliable asset in retaining muscle mass during a diet than protein alone. This hypothesis can be further confirmed by the numerous studies comparing the effects of weight loss in resistance trained vs non-resistance trained individuals. The people lifting weights time and again effectively maintain, and in some cases increase, their lean mass while dieting.
Think of this in terms of "use it or lose it." Muscle is metabolically "expensive," and if your body perceives that it no longer needs it in order to survive, it will allow its muscle tissue to waste away for the sake of energy efficiency. Why maintain something, if it no longer serves an important survival purpose?
We can avoid muscle loss, however, if we provide the body with an adequate reason for it to hold on to our muscle (i.e. we need to resistance train).
But How Much Resistance Training Is Required?
Researchers have been looking for definitive answer to this question for years. Moreover, they're still searching for an end all be all answer.
Work by Taaffe et al suggests that progressive resistance training done with 3 work sets at 80% of one's 1 repetition max performed just once a week "improves muscle strength and neuromuscular performance in older adults." Moreover, training just once per week did not yield noticeable differences in comparison to subjects who trained more frequently.
In another study from the British Journal of Sports Medicine researchers determined that "[o]ne set of exercises performed once weekly to muscle fatigue improved strength as well as twice a week" in older adults.
Research on younger subjects reveals similar findings. Work conducted by researchers, published by The Journal of Strength and Conditioning Research, reveals "that for pubescent male athletes, a 1-day-a-week maintenance program is sufficient to retain strength."
A research review conducted by Wornbom et al in 2007 suggests that differences in the frequency, intensity, and volume of resistance exercise do not yield noticeable differences in muscle hypertrophy and strength. The researchers state, "[t]he results demonstrate that given sufficient frequency, intensity and volume of work, all three types of muscle actions can induce significant hypertrophy at an impressive rate and that, at present, there is insufficient evidence for the superiority of any mode and/or type of muscle action over other modes and types of training." Thus, we may conclude that most any type of resistance training can, and will work.
This research review in particular may serve as a potential explanation for why so many different effective weight training and muscle building programs seem to saturate the internet.
Why do so many seemingly contradictory methods of weight training work?
They work because they do.
This answer may seem a tad redundant (and it is), but it may just be the truth. So long as we provide some form of resistance training, whether high volume, low volume, high frequency, low frequency, high intensity, or low intensity; so long as we provide some sort of external stress that necessitates the maintenance of or increase in muscle mass and strength, we're in good shape.
My Recommendation
While I could just say "do whatever, because anything will work," doing so would be rather fallacious and irresponsible.
By looking at the above research, particularly the first two research studies I mentioned, I recommend that you do between 1-3 work sets done to muscular fatigue in 6-8 reps with pertinent exercises at a frequency of once every 5-7 days. Additionally, you should ensure that the resistance you're using progressively increases over the course of time. Continue to add 5-10 pounds of resistance to your exercises so long as you continue to be able to perform 1-3 sets of 6-8 reps for said exercises.
So what exercises do I recommend?
The following program ought to do the trick:
Any sort of Chest Press/Dip 1-3x6-8
Any sort of Military/Shoulder Press 1-3x6-8
Any sort of Row 1-3x6-8
Any sort of Lateral Pull-down/Chin-up 1-3x6-8
Any sort of Leg Press/Leg Extension/Squat 1-3x6-8
Any sort of Leg Curl/Straight Leg Deadlift/Glute Raise 1-3x6-8
This program should be enough to allow you to maintain, and perhaps even build, muscle mass while you lose weight in conjunction with the methods I outlined in Parts I & II of this series.
What About Cardio?
I've actually already discussed cardio in a previous post entitled Exercise in Review: "Cardio". Rather than repeat myself, you can just read the post.
That's All She Wrote! (Well, Actually He, That Being Me)
This 3 part series only scratches the surface of potential options for effective fat loss methods. Give them a try, but know that there's nothing truly revolutionary about them.
Understand, however, that there are no quick fixes. A healthy life demands a healthy lifestyle. Yo-yo dieting often results from an inability or a lack of willingness to make effective changes in one's habits. Too many people like to make extreme changes in their diet/exercise, fully expecting that will power will be enough to keep them on track. It just won't work (I think the popular TV show Biggest Loser adequately illustrates this point).
Don't make a reliance on will power your long term means for achieving health. Rather, use will power as a short term tool (sort of like a scaffolding) for developing long term habits. (For a closer look at the subject of addiction and habit, I recommend the book Addiction and Virtue: Beyond the Models of Disease and Choice).