I hear it all the time. "Chris, my fat loss has slowed down. Should I drop calories again?" Then I find out these guys are already eating like Girl Scouts. And not those nice husky Girl Scouts either.

There are limits to calorie reduction – a line in the sand where the negatives outweigh the positives. But there are also drawbacks to doing more cardio. We asked Dr. Lowery set some guidelines and give us the real scoop. – Chris Shugart

The Decision

If your goal is fat loss, then there's going to come a time when you have to make a decision: How much more am I going to diet? How much cardio or extra exercise am I going to do? Which is better?

Typically, there are four basic strategies when it comes to getting ripped:

1 – Drugs

Most of us aren't going to go this route, nor do we need to, but I have to mention it because it's a method commonly used by professional bodybuilders.

I was reading an old bodybuilding interview from the Tom Platz era where the competitor said, "Oh, you really don't need a lot of cardio." I'm thinking, well, you didn't, dude!

But if you're not artificially elevating your basal metabolic rate, jacking around with lots of thyroid meds, clenbuterol etc., then at some point you have to bring cardio into the equation.

2 – Cardio

There are two basic types here: the non-panting, semi-fasted variety that I've written about before and high-intensity work like sprints and intervals. These can be used in conjunction with each other or independently depending on your state of training.

3 – Food Restriction

Sure, this is obviously part of any diet plan, but you can only push it so far.

There's a miniature literature review here on the site that outlines how far one can go while avoiding "starvation mode" (metabolic slow-down) by sticking to just moderate kcal restrictions.

4 – More Weight Training

Although we don't think about it often, a longer weight-training workout does lead to extra calorie expenditure, some derived from fat oxidation.

We shouldn't forget that hitting the iron itself increases subcutaneous abdominal fat breakdown and "burning." (Ormsbee, et al. 2009) If you're going to try to avoid cardio, your only other options are more volume, finishing work, or accessory work during your regular training session.

Of these four strategies, two get the most attention: cardio and diet. So let's take a look at each and establish some guidelines.

Calories: How Low is Too Low?

You've heard this applied to other topics, and it's true for calorie intake as well:

"You can only go so far to the left before you've got to go back to the right."

How many calories can you get away with before your metabolism really slows down and you go into starvation mode?

Starvation mode is something you have to avoid at all costs. Your basal metabolic rate (BMR) is about 65 or 70% of all the calories you put out every day. So when you slow that down, even a cardio workout that burns 400 calories may just be making up for a depressed BMR.

In the classic underfeeding studies in the 60's and 70's, college-aged men were fed 3500 calories per day, then dropped to only 450 per day. These poor guys experienced up to a 45% drop in BMR in a single month. (Bray, G., 1969)

That's true starvation mode: their bodies were trying to keep from dying, their metabolisms were "panicking" and slowing down because it was assumed they were in the middle of a famine.

When you do a literature review, the magnitude of reduction becomes fairly clear: somewhere around 600 or 700 calories less than your maintenance intake is about as far as I'd want to initially go.

What's maintenance intake? It's about 3000 kcal per day in a typical (non-lifter) college male. (Borel, M., et al 1984)

Okay, so if the average college male needs 3000 calories per day, the first step might be to drop to 2400. That's definitely below maintenance for any adult male who's lifting weights.

That may be the first stage. I don't think it's a good idea to jump right into a very aggressive diet. You probably aren't relying on lots of drugs, so you really have tiptoe here – or at least show some respect. Ease calories down in a more controlled manner rather than going from a full-on mass phase to a crazy-strict 1600 calorie diet.

Hormones change fairly quickly in response to eating patterns. As my old endocrine professor said, "When it comes to hormones, you have to nudge the body." You don't force it, because then homeostatic mechanisms kick in and make you pay the price tenfold.

It's not that painful to get down to a 2400 calorie intake. If you do something practical like cut the carbs out of your dinner and stop drinking calories (other than protein shakes and peri-workout drinks), you can get there easily. Just cut out the obvious junk food and 2400 is an easy mark to hit.

Do that for the first month or so. After the first month, you're used to eating clean: no more junk, a lower carb dinner, etc. Then, in a month or two, continue the negative calorie balance with some cardio rather than dropping calorie intake again right way.

I like the non-panting morning variety (walking on a treadmill) because it doesn't overtrain you. You're not crossing any stress hormone thresholds. That said, you could do some high-intensity interval work after your weight-training workout if that's your preference. I've been known to switch to this when I really needed the extra hour of sleep the prior morning (making pre-breakfast cardio impossible).

But frankly, I usually don't have anything left in me after the weights. When I hear people say they do "lots of interval work" after their regular workouts, I worry that they're not going to achieve their best muscular gains. That can be easily overdone: you're dividing your body's resources – half into the weights and half into the constant aerobics training. Not good.

Although controversial due to methodological differences, sub-optimal training responses have been well-documented in spaceflight, military, and other studies. (Carrithers, J. et al. 2007; Docherty & Sporer 2000; Dolezal & Potteiger 1998; Dudley & Djamil, 1985; Santtila, M., et al. 2009.)

Now, at bodybuilding shows, I hear my fellow competitors talk about how they quickly reduce calories to very low levels, then stay there for 12 weeks. Well, in open competitions, when the competitor is on lots of "gas," he can do that. I can't, so I try to coax the body fat off with a 20-week diet that starts "easy" and gets more aggressive toward the end. This is not only metabolically smarter, it's psychologically better – for me at any rate. It builds momentum.

During the first month, I just cut down the calories moderately. (Sometimes I'll do some very limited interval work on the bike just to set the stage for the following month.) The second month I add in regular non-panting cardio, keeping calories the same. With the pre-breakfast style cardio that I do, I usually drain off 400 more calories.

So if you're eating 2400 kcal per day, you're now down to 2000 in a sense because you're "bleeding off" another 400 with the extra work. Now you're in a calorie deficit through a combination of dietary manipulation and cardio.

Practical Tip: If you're using a piece of gym equipment that claims to measure calories burned, it damned well better ask you what your body weight is.

If it doesn't ask you, it's going to assume you're a 150-pound dude. If you're not, then you're burning far more calories than it tells you.

That's still no guarantee that it's accurate. Those consoles on the cardio machines are just glorified calculators, not portable metabolic carts, but at least it's a step in the right direction.

The Exercise Factor

Remember, exercise is not just anti-eating. Exercise builds structures like capillaries and mitochondria. In other words, exercise builds your fat-burning machinery.

Let's say your maintenance level is 3000 calories per day. After a month or so of easing calories down, you drop 600 calories, then spend another 400 calories on cardio several days a week. Now you're 1000 calories sub-maintenance.

Now is when you have to start making decisions based on your results and individual needs. You're eating less and doing more cardio – you're pushing it pretty hard. At this point, I'd suggest a couple of things:

First, if you feel like the diet is really easy, maybe you can restrict down again food-wise. You take it down to 2000 calories of food per day if you're not already there.

Second, if you're already having a tough time with diet, the flipside is to add more calorie output in some way with physical activity. If you're already doing the fasted morning stuff, maybe you try some HIIT after a weight-training workout, or vice-versa. If you can't do both because of your schedule, you can start adding sets in the gym.

Once you're 1000 calories below maintenance, you really have to decide whether you're fresh enough to do this physically or dietarily. It's a subjective call. If this is coming at the end of month two or during month three of your cutting phase, and you find yourself having a tough time sleeping, getting head colds, upper respiratory tract infections, or cold sores, you're probably overtraining.

There's a clear link between your immune system taking a hit and overreaching. Your body could be saying, "Listen, I'm struggling here. Enough with the extra exercise volume!"

Practical Tip: Use motivation to train as a feedback mechanism. The lower your motivation level gets, the more burned out you're getting. In addition to sets and reps, I always log training motivation on a scale from 1 to 7.

Use this to decide where you're going next. If my motivation to train was humming along at 6's and 7's and now it's routinely a 3 or a 4, I'm burning myself out. Now I know not to add any more cardio or sets in the weight room.

I do the same thing with hunger. This is where experience plays a roll: Is it "munchies" calling, or is it true depletion? There's being "empty and weak" and then there's "wishing you had a bag of chips." The latter is just your love handles calling. The former may be your muscles calling, so go ahead and feed them a little.

The 1200 to 1600 Calorie Rule

As a rule of thumb, most authorities will tell you – rightly – to never go below 1200 calories a day. But frankly, that's usually for smaller women or for those who aren't physically active. Why 1200? Because you can't possibly get all the nutrients you need from a variety of foods with a ceiling below that!

For college men, I'd never go below 1600 calories per day, and then only temporarily. That's ridiculously low, especially if you're already doing cardio as part of your plan.

Right now I'm two weeks from a bodybuilding show, in strict contest prep mode, and I'm sitting at 1600-1800 cals. Let me tell you, it's not even fun right now! I'm just trying to hold myself together. The little nagging injuries are starting to accumulate. (Then again, I'm 42, with lots of mileage on this chassis.)

In any case, if you're strung out and under-eating, you may start cramping and getting little injuries that just don't go away. This is especially obvious to the older, more experienced lifter. That's because you're eating so little that your tissues just aren't turning over.

Let's say you're well into a diet, say month four (weeks 13-16 out of 20). You're at a rock-bottom 1600 kcal per day and doing cardio. First, realize that this isn't sustainable. You should have a target date where the diet is "finished." Now, consider NEPA.

The NEPA Factor

One of then things I have people do is buy a pedometer that measures steps taken per day. First, get some baseline data of how many steps you take when you're eating well – your normal diet. Let's say you're walking around getting a good 8000 steps per day.

But now, months deep into your diet, you look down and you're getting 4000 or 5000 steps per day. You're moving around less in part because you have less thyroid and leptin. You're less energized. You're sluggish. Your body is trying to conserve energy.

This decreased NEPA (Non-Exercise Physical Activity) is yet another factor to keep in mind. It's one more thing you can "ballpark" measure.

I don't think people really understand NEPA. Most of us are closer to sedentary than we think, even if we go to the gym and do our cardio. To achieve "very active" status in one of those formulas that determines your calorie needs, you have to have a manual labor job, then go work out, then go dancing all night!

Most of us fall into the middle of the NEPA category: light to sedentary work but with intense recreational exertion. Overall, this may be considered "moderately active" in one of those dietary software programs. That's where I fall as a bodybuilding college professor.

The Supplement Edge

If you're afraid that your BMR is slowing, consider supplements. Caffeine will boost it by about 10%, and so will Spike® Energy Drink or Hot-Rox® Extreme. Plus, good ol' water helps with thermogeniesis. (Boschmann, M., et al. 2003) So you may want to swig down your supplements with plentiful, cold H20.

So What Have We Learned?

Exercise results in a small magnitude of body weight change, but it's long in duration (lasting). In other words, for those who start to exercise but don't touch their diets, they'll have modest results, but those results will last forever if they keep exercising.

Diet is the opposite. Dietary changes tend to be dramatic. You can lose 10, 20, 30 pounds, but it's not long term, especially if it's not accompanied by training. The long term success rate of restrictive stand-alone diets is dismal (perhaps about 5%) over eight years.

This illustrates why it's important to do both: exercise and eat right. You can take small steps and increase one but not the other, or you can do both at the same time, intelligently, for faster results.

How much exercise is too much? If you experience lack of motivation and are getting sick or injured, you've already gone too far. As a best guess for most people, two hours a day is the top-end. That could be an hour in the morning and an hour at night.

Ectomorphic people, who tend to be thinner and more angular, may only be able to get away with 90 to 120 minutes per day.

Very robust endomorphs or mesomorphs, those who genetically carry more fat and muscle, may be able to get away with 2.5 hours of exercise per day.

For calorie restriction, 1600 calories is rock-bottom for the average T NATION reader. My advice is to take your time getting to that level, then have a targeted end date. I like 20-week diets.

Remember, you can't keep cranking the diet knob and lowering calories forever. Instead, switch gears: do extra sets, add cardio, or add supplements.

References and Further Reading