Last week, I made the suggestion that people interested in maintaining health and immunity while avoiding excessive oxidative stress should expend no more than 4,000 calories per week through focused exercise, a recommendation that I’ve found to be pretty sound for most of the general population. You guys had plenty of questions about that recommendation, as I expected, so today I’m going to devote the entirety of “Dear Mark” to answering some of those questions. I didn’t get to all of them, but I did try to tackle a representative swath. Don’t expect big sprawling walls of text; I’m just doing this rapid fire style. If I’ve made any glaring omissions, let me know and I’ll see if I can answer them at a later date.

That said, let’s get right into it:

This makes my daily 16-mile round trip commuting through London bad for me then?

When I talk about a 4,000 calorie limit, I’m talking about formal, focused exercise: weight lifting, running, sprinting, cycling, circuit training, CrossFit, training for a 5k, 10k, or half marathon, arduous hikes. If you set out with the mindset to “get a workout in,” you should count that toward your “limit.” If you end up sweaty and breathless and feeling like you’ve just done some real work, you’ve done focused exercise that counts.

If you have to ask, it’s probably not. If it were too much, you’d know. You’re probably so used to it and the relative intensity is such that it’s not much of a stressor. Cycling, right (walking 16 miles a day would be pretty nuts)? It’s free activity, in my opinion. It doesn’t really count.

Plus, that’s your commute. You have to do it. Even if you’re going over the 4,000 calorie “limit,” what can you do but make the best of it? This is just a guideline to keep in mind.

If 4,000 weekly exercise calories is the maximum recommended, what would be the minimum weekly exercise calories?

I hesitate to give a minimum calorie figure, so I’ll give a minimum recommended fitness regimen instead:

One or two strength training sessions a week. Weights, bodyweight, rocks in your yard, sandbags, kettlebells, anything. Just lift some heavy things. If you go once, you’re really gonna have to make it count.

One intense movement session a week. Sprints, intervals, circuit training, maybe a CrossFit WOD. Something that makes you move quickly and safely for about 20-30 minutes (counting the breaks in between intervals, sprints, etc). Think metabolic conditioning.

Lots of moderate activity. Walking, hiking, light jogging, cycling, swimming. Just move around a lot, usually a slow pace, but occasionally picking things up a bit and elevating the heart rate.

Choosing a minimum expenditure is tough, because the quality of calories expended is what matters most on the low end. You could lift a couple times a week, sprint once, and do lots of walking. You wouldn’t necessarily “burn” a ton of calories, but you could get lean, strong, fit, and healthy on that routine because the quality of calories expended was exemplary. At the high end, hitting 5,000, 6,000, 7,000 calories expended is going to be rough on your body no matter their quality.

Any hints for adjusting this – I weigh about 2/3 what your theoretical 185lb. fella does… Should I be thinking in terms of 2/3 the time, the ‘calories’, the road miles….? Will it basically adjust automatically because it ‘costs’ me fewer calories to haul myself around?

Oy, I’m talking about calories.

Also – when you say stuff like walking around doesn’t count – you mean it doesn’t count for purposes of this cutoff, right? It still ‘counts’ toward making us generally happier, perkier, etc…. right?

Yeah, this is just a really rough guideline. A big guy will burn 4,000 calories a little easier than a smaller guy, who’ll have to put in a bit more work… but 4,000 is a good target to shoot for in my experience. You could add up to a 1,000 calories for bigger guys and subtract up to 1,000 for smaller people and you’d still be in the general ballpark.

And of course, walking counts toward happiness, health, and general mobility, so you should definitely do it as much as you can. It just doesn’t matter in terms of caloric expenditure.

Did those studies control for food in? I would imagine the average person at super high levels of activity is eating more and likely eating more higher carb foods, including all of those nasty in-activity gels, blocks and other forms of corn syrup.

I’m curious if a sample exercising at 4,000+ calories/week but making it up with high quality fat and protein would see the same ill effects.

Well, that’s just it – when you start getting into the upper echelons of caloric expenditure, you almost have to rely on the cheap sources of refined carbohydrates, just to get by and keep your head above the water. This is necessary to keep up your energy output, but it’ll mess you up in the long run. Not only will the activity induce excessive oxidative stress and impair health, the food will do it, too. Plus, you’ll only enable your excessive activity even more.

Trying to maintain a heavy exercise schedule (especially if it’s heavy on the glycogen-burning cardio) on just fat and protein – no matter how grass-fed, raw, and/or organic it may be – won’t work out too well. It may even be more stressful, as you’ll be working overtime to produce enough glycogen from protein to replenish the stuff you burn. Of course, since you’ll burn out and eventually figure out that maybe you should change things up, maybe it’ll work in the long run in a roundabout way.

That’s why I recommend that health-focused individuals stick to a moderate, smart exercise program without “too much” caloric expenditure: to reduce the need for cheap, refined, excessive amounts of carbohydrates. It’s easier on your body, it doesn’t preclude excellent fitness levels, and it allows you to eat nutrient-dense, Primal fare.

Wow, this is really food for thought. I am in my late 50?s and don’t think I burn anything close to 4,000 calories per week. I don’t do any formal exercise, but I farm on a small place and do a lot of walking and hauling. I am the most muscular I have ever been in my life, and for the first time in more than 25 years, feel like my weight is under control and stable. I’m not sure what to do with this post since my life seems to be working as it is, but I don’t want to ignore something that may contribute positively to my longterm health.

4,000 calories is the upper limit. Hanging out below that threshold is perfectly fine, and perhaps even ideal or optimal. Heck, from what you’re saying – lots of walking and hauling, more lean mass than you’ve ever had, weight stable for the first time – you should absolutely keep doing whatever you’re currently doing. Whenever your “life seems to be working as it is,” rejoice, for you have attained what we’re all pretty much chasing.

Isn’t a leisurely ride round the neighbourhood and a stroll to the store moving frequently at a slow pace? No mention again of “natural” exercise, working in the garden, chopping wood etc as well as taking the stairs instead of the lift etc and just trying to incorporate more natural movement and exertion into your daily life.

Yep. I love all that stuff and you should do it as often as possible. Daily, integrated movement is essential. I didn’t explicitly mention it last week, however, precisely because it doesn’t “count” toward the calorie expenditure upper limit. It’s “free.”

I agree with Mark (or thought I did?) that these are more likely the natural gaits for homosapiens most of the time – that we were, in fact, NOT “born to run”, at least not long distances at a time. Isn’t PB and PBF about getting away from medium/high exertion, long duration? Long being more than a minute or so?

Not exactly. The “Chronic Cardio” I’ve always railed against refers to high exertion, long duration, steady state training where your heart rate is in excess of 75% of your max. It’s the ceaseless pushing that breaks you down. It’s the high volume that hurts you, the miles and miles you pack away. I’m not against long duration training as long as the intensity is mild enough. I’m not against high exertion training as long as you take breaks (intervals) or keep the duration short. Think of the ancestral persistence hunt – lots of walking and crouching down to follow tracks interspersed with light jogging and full out running – which was absolutely not done at “marathon race pace.”

Thanks for reading, folks, and I hope I covered the questions you needed answering. Send along any more, and if there are enough to warrant a new post, I’ll try to answer them in the future.

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