I've been waiting for Cap to answer this one too. I don't know the specifics about timing, etc., either.

The weight lifting is technically what causes improved strength and muscle building. Your muscles get torn from weight training, and repair themselves stronger. The repair part requires protein since protein is what muscle is. When your body does not have enough protein, it will break down muscle from other areas for the amino acids required. Not enough protein also results in longer recovery times, more muscle soreness, and a lack of results.
I think lifting prior to cardio will result in faster/better results. However, if you are not looking to bulk up like a beefcake, I don't think it really matters. It wouldn't hurt to allow some time and carbs to pass between the two if possible though.

lift heavy, do warm up lifts before you go heavy. Do cardio after (if at all). You will build muscle quickly, you are a girl, you CANNOT bulk up for you have no testosterone, unless you are taking steroids. I do the stronglifts 5x5 program, google it or look up the thread on mfp. I've been slacking really badly and not gained weight because my metabolism is boosted from the extra muscle growth. I take protien powder. You can only bulk (get fat) if you take in more calories than you burn. So if you are meeting your protein goals you shouldn't supplement. I like the ones that have a fairly high protein to carb ratio and usually have stevia for the sweetener. I don't know anything else on it as far as protein aspects and how they are used differently except for anecdotal evidence.

And since I'm already asking one question...I have also read and had people tell me to do weight lifting first, then cardio, because you will be able to lift more therefore gain more muscle by doing the weight lifting before you tire from the cardio. As I see it, one will be done while you muscles are tired either way...I like to do the cardio first because then I'm all warmed up. Is there any scientific proof to one being better than the other? I want to gain muscle but not interested in bulking up. Molly

(p.s., because you are a teacher I double checked my spelling.)

You do weight lifting first because you will be stronger due to higher glycogen stores. That means you can lift heavier poundages and more intensely. Deplete them through cardio first (any exercise will use glycogen first) and your energy level will be lower and also you then break down muscle to fuel the rest of your strength workout. Counter productive. Lift first.

Also you CANNOT gain muscle on calorie deficit. You have to be in calorie surplus. For every pound of muscle you gain, you'll gain a minimum of .3lbs of fat along with it or even higher.

A.C.E. Certified Personal Trainer
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Been in fitness for 28+ years and have studied kinesiology and nutrition

but if I don't have a calorie deficit, I also won't lose weight will I? Doesn't it all come down to cal in vs. cal out in the end?
I need to lose probably 70 or more pounds, and I have been concentrating moselty on burning the most calories by doing cardio.


by the way, thanks for your answers everyone!

Yup, calorie deficit to lose weight, surplus to gain muscle. You can't really do both at the same time. That's why body builders work in cycles of cutting and bulking. You can still feed your body protein and do strength training to help maintain your muscle mass so you don't lose as much of it during weight loss.

I know I've been AWOL due to family and end of term issues, but I'll take this on here.

First, consider skeletal muscle as a tissue. Muscle cells are essentially tubes (they are called muscle fibers for a reason) filled with lots of protein threads (properly called myofilaments). It is these protein fibers that make the muscle contract.

Skeletal muscle fibers come in many different forms, but two primary forms are typically discussed. Fast twitch (also called glycolytic) fibers are larger (i.e. have more protein fibers), produce more power when they contract, but are very dependent on anaerobic metabolism. Hence they fatigue very easily and don't use oxygen terribly effectively. Slow twitch (also called oxidative) fibers are smaller (i.e. have fewer protein fibers), produce less power when they contract, and are equipped to rely on aerobic metabolism. These cells have low glycogen stores but store oxygen using a protein called myoglobin and are very fatigue resistant.

(An important aside on protein. Proteins are large molecular chains of building blocks called amino acids. Every protein is one or more chains of these amino acids folded into intricate, complex shapes. I've seen protein powder rating sites rank protein based on how rich it is in amino acids. This is one of the single most nonsensical notions I've seen come from the fitness world...all protein by definition is rich in amino acids...it wouldn't be protein if it weren't. All my colleagues have laughed when I've shared this idea with them.)

You are, essentially, born with all the muscle cells you will ever have, as these cells do not undergo mitotic division. They transfer between the two primary fiber types described based on usage. If you want large muscles, you need to develop more fast twitch fibers. This requires resistance training (weight training is a common example but not the only one) to drive the muscle fibers to transform. As fast-twitch fibers have lots of protein fibers, they require amino acids from the diet to build the new fibers. Hence, building muscle requires a specific type of exercise (resistance) and ample protein in the diet to supply the raw materials for building the new protein.

Muscle can only be built with protein. Carbs and fats won't do it. That's why protein is essential or you will have muscle catabolization.

This is not an accurate statement. While carbs and fats don't contribute raw materials, protein is the least efficient of the three for producing the cellular energy source called ATP (adenosine triphosphate), which is a modified nucleotide, specifically a version of one of the components of RNA.

(Another aside -- In a recent forum post about ATP, many MFP members were claiming we don't take this in dietarily. As a point of fact, we do! We have enzymes produced in the pancreas for digesting DNA and RNA and transporters in the small intestine to uptake nucleotides...hence, ATP is broken down and up-taken as the A RNA nucleotide for those who know molecular genetics.)

Anyway, protein synthesis is an energy intensive process that requires three things in muscle cells: (1) amino acids as raw materials, (2) resistance training to stimulate the muscle fibers to change form, and (3) ample ATP to power the chemical reactions that will assemble the proteins. Carbs and lipids in the diet provide the energy to form this ATP. So while strictly speaking, those two macros aren't directly involved in the building of protein, they are crucial to supply the energy. This is where the caloric surplus comes in.

Loss of protein from muscle (protein hydrolysis or catabolization) is not inherently bad as many suggest. Consider the body shape and muscle size of endurance athletes. They do not have large muscles. When cardio training dominates your routine, your muscles shift toward the oxidative fiber type. Being highly endurance resistant means giving up space for protein for mitochondria (cellular organelles that produce ATP aerobically) and rough endoplasmic reticulum (cellular organelle for building proteins...in this case, the enzymes for driving aerobic metabolism). In my personal case, I'm not interested in strength for its own sake. I strength train to maintain a base level but focus more on cardio to improve endurance. As leg muscle has converted to slow-twitch I've given up muscle mass...and am a better runner for it. (This is not the same as atrophy which is a loss of mass to disuse, and should not be confused as such.)

Fiber type switching is not a function of caloric deficit/surplus. Thus, if you strength train while in deficit, you can produce fast-twitch fibers (though growth will be limited) and improve relative power (as this is more complex than size, I will not address it here). In the end, there is a trade-off between power/speed and endurance. You cannot physiologically specialize a muscle to do both. Period.

Ultimately, if your goal is to lose weight but improve muscle definition, run a caloric deficit (to keep yourself burning fat stores as one source of cellular energy), keep your protein high (to provide the amino acids to maintain myofilament proteins within muscle), and strength train appropriately. (The advice about cardio second is sound. As strength training is inherently anaerobic it requires easy sugar access (hence stored glycogen that can quickly be converted to the precious glucose), so pre-exhausting the glycogen supplies limits strength training. Since proper cardio depends more on released fat stores and circulating glucose, it is less limited by glycogen...and again, properly trained slow-twitch fibers don't store much glycogen anyway.) Protein powder can provide a supplemental source of dietary protein and depending on how it is used, it can be used either to lose weight (low levels with a caloric surplus) or build muscle (high levels with a caloric deficit). In the end, the diet must support the exercise and the exercise must be consistent with your fitness goals.

Cheers!
Cap

Going to have a good read later!!