How to Maintain Muscle While Losing Weight

?Losing weight? is insufficient terminology. It?s too vague, too unspecific. When a person sets out to lose weight, just what are they trying to lose? Bone density? Muscle mass? Organ weight? Of course not ? they?re generally looking to lose adipose tissue. People want to burn body fat, and they want to do it without negatively impacting the more beneficial sources of (corporeal) gravitas. Simply put, you want to lose fat, not muscle. The only problem is that the popular methods for shedding weight often result in excessive (but really, any amount is excessive) muscle loss, too. I?m talking, of course, about precisely the practices I rail against in the Primal Blueprint ? Chronic Cardio, ultra low-cal/low-fat ascetic dieting, and other trappings of Conventional Fitness Wisdom. Granted, adhering to any, individually or in concert, will probably help you lose weight, but a ton of it will come from your lean mass (not to mention bones and organs). That said, if you?re going for skinny-fat chic or the waiflike, undernourished look, feel free to run fifteen miles a day and live off canned tuna and rice cakes. The scale will drop, and you won?t be weighed down by that pesky musculature any longer.

But you don?t want that (do you?). You want a strong, lean body. You want to maintain your agility, your power, your strength, and your agreeable appearance. You want to burn fat while maintaining (or even building upon) your existing muscle. Heck, if you?re mostly interested in burning fat, you need the muscle. Muscle is a hungry, wasteful thing. It craves protein and fat to run effectively, along with a bit of glycogen every now and then to fuel up. Next to the organs and the brain, your muscle mass is one of the biggest consumers of energy in the body, and the more you have, the better your fat loss. It?s a delicious cycle ? the right kind of exercise spares muscle and burns fat, and more muscle with reduced body fat allows you to do the right kind of exercise.

To make sure you?re losing the right kind of weight, you have to chart your progress. It?s a little more complicated than just watching your total weight, though. In fact, you don?t even really need the scale anymore. Well, you can keep it around, but don?t get too comfortable; your meetings will be fleeting and infrequent from here on out. Spend a little quality time alone, if you must. Get your fill of each other, because you?re going to be using an entirely different set of barometers to monitor your weight loss: eyes, ears, belts, and weights.


Check yourself out. Don?t hover in front of the mirror, though. Strip down to the bare essentials and take full body snapshots, making sure to space them out every few days. A lot of people tend to obsess over minor daily fluctuations, but you?re not going to see a whole lot of visual differences that quickly. Five days, six days, or definitely a week, however, can be enough time to notice a difference in a direct comparison. Look out for misshapen lumps, sagging chests, flabby underarms ? all signs that you?re losing muscle and maintaining fat.


If you?re doing it right, you should be getting noticed. Whether it?s a significant other, a co-worker, or friends, people will compliment you. Heed their words. When people say, ?You?ve lost weight!? (and they?re not your grandmother clicking her tongue in disapproval) and, “You look stronger and healthier!” it means you’re on the right track. Take it as a sign.


Losing fat and maintaining muscle means dropping pants sizes. Using an extra notch on the belt is good. Having to buy an entirely new belt is better. Using a hole punch to create new holes because you can?t afford a new belt is pretty bad ? but at least you?re still losing fat.


The best way to ensure you?re maintaining muscle mass is to chart your progress in the weight room. Muscle loss is accompanied by a reduction in strength, so if you find yourself failing to hit the marks you used to destroy with ease, you?re probably eating muscle. It?s a bad sign if you?re dropping weight and doing fewer pull-ups than before.

(You can also use body fat testing to get actual numbers, but I?m a big fan of the above methods. How you feel, look, and lift is going to be enough of a marker for most people.)

Okay, those are a few ways to monitor your progress (or lack thereof), but what about actually doing it? What should we be eating, and how should we be exercising? Short answer: follow the PB way. Eating a high-fat, moderate protein, low-carb diet is pretty crucial in our everyday life, and it?s no different now. Minimizing our insulin load while filling up on fats, meat, and veggies is just as important. Likewise, lifting heavy things and running really fast every once in awhile are keys to promoting fat mobilization and muscle maintenance. You could even just check out the last post I did on building muscle and for the most part all that stuff will apply, too.

But there are a few specifics that bear repeating, and a few areas where today?s advice differs slightly from that of the previous muscle-building post.

Intermittent Fasting

IF is perhaps your greatest tool when losing weight and maintaining muscle. It increases insulin sensitivity (good for mobilizing adipose tissue), promotes the secretion of growth hormone (a muscle sparing, fat burning hormone), and reduces body fat. What?s not to love? It?s almost like the human body?s response to IF was designed specifically for our current predicament. Hmm, I wonder if Grok ever found himself in a situation where food was scarce and muscle mass was precious? For extra benefits, exercise in a fasted state and wait at least an hour before you eat something.

Avoid Excess Chronic Cardio

I know, I know, those words probably still sound like sacrilege to a few of you, but it?s true that constant, Chronic Cardio is catabolic ? it retards muscle growth, interrupts protein synthesis, and can even reduce existing muscle mass. Too much exercise (especially highly stressful long distance steady state stuff) releases cortisol, a vitally important ?flight-or-flight? hormone that can be incredibly damaging in unnaturally large amounts. In Grok?s day, cortisol would have kicked in when he needed it to jog his senses and get him focused on surviving a momentary threat; nowadays, we?re pelted with stress from all angles, and our body doesn?t differentiate between artificial stress (like work, traffic, or money) and ?real? threats. Chronic Cardio is just another unnaturally stressful situation we subject ourselves to, and cortisol is happy to help ? except all that help packs on the pounds and eats away at our muscles.

Make Sure You Sprint

Besides, sprinting (or really, any exercise that stimulates lactate production) is a great way to increase growth hormone production and burn body fat while maintaining fast twitch musculature. GH, fasting, sprinting, fat mobilization… it all seems to fit together, huh?

Lift Heavy Things

You fail to move it, you?ll lose it. You can?t forget about lifting, whether it?s with a heavy barbell or your own weight. Resistance training increases bone density, which is an important factor in healthy body weight, and it (obviously) also increases (or maintains, depending on your diet/intensity) muscle mass. Oh, and I probably don?t even have to say it, but heavy lifting (especially compound exercises like squats and deadlifts) also stimulates growth hormone production.

Don?t Go Overboard on the Food

You?re not trying to pack on weight ? even if it?s muscle ? so there?s no need to stuff yourself. When you?re not fasting, just eat normally. Eat your fill, and stop when you want. Just keep those carbohydrates low, no more than 50g or so for most people, and don?t obsess over calorie counting (in either direction). Focus on saturated and monounsaturated fats (with some fish oil to supplement) and take in about a gram of protein for every pound of lean body mass.

Again, you?d be pretty safe just following the normal Primal eating and exercise plans, getting plenty of rest, minimizing stress, and fasting once in awhile, but I figured a quick and dirty guide with a few clarifications would help ensure you achieve fat loss without sacrificing muscle mass. It?s just too bad that most of the mainstream assumes muscle loss accompanies weight loss ? if they even consider it. Let?s hope a few outsiders stumble upon this and realize weight loss doesn?t have to be a compromise.

Shoot me some questions or concerns, if you got ?em! I?m happy to help.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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