Method for Achieving Calorie Deficit

Hi Jordan,

When it comes to maintaining muscle mass while in a calorie deficit, is there a difference between A. Doing minimal cardio and eating less, vs B. Doing extensive cardio and eating more? To put numbers on as examples, I either A. Run for 60-75 minutes per week, burn 2800 calories per day and eat 2300 calories, or B. Run for 20-30 minutes per week, burn 2600, eat 2100.

This is assuming that in both cases same amount of resistance training is performed and same amount of protein is consumed (1gm/lb of bodyweight) with extra calories in case B coming from carbs.

Thanks.

Yes, only option A is going to work.

Can you explain a little more why this is the case? Does it have to do with your IG story post about how your 15k steps likely didn’t increase your TDEE? I was thinking of posting a question about this because I’m in a similar situation to OP.

The one thing I don’t understand is, if cardio doesn’t matter in the case laid out above, then how come the NIH planner asks for your activity level and assigns different calories based on the response?

Got my A B and B A mixed up there. I assume you mean the minimal cardio route is the way to go.

To be 100% clear, I think you and everyone else who is able to, should meet the physical activity guideline minimums. I just don’t think that adding a bunch more of conditioning on top of that is likely to help with weight loss that much. Weight maintenance, sure.

Physical activity is about 20-40% of TDEE, but raising physical activity a whole lot doesn’t tend to increase this further. In short, you need moderate levels of activity and doing more than that probably isn’t going to increase TDEE that much whereas doing less is likely to be deleterious to your health.

Is that because the body puts itself into “energy saver mode” and burns less resting calories? So any extra calories you burn doing high intensity cardio will be offset by the body burning less when resting?

If correct, does the same principle apply to sleep? Less sleep causes the body to conserve energy and you end up burning less throughout the day and thus not recover efficiently?

Not really and certainly not always. That’s the activitystat hypothesis, which is not supported by evidence. There just seems to be an upper constraint to how much energy we expend in a day. This probably doesn’t come into play until we’re well above the activity guideline minimums.

The same principle does not apply to sleep.

Ah got it. So to make sure I am understanding this correctly:

If I am in a caloric deficit and I go on a 3 hour mountain bike ride that burns 1,300 calories (arbitrary number, plus I can’t say with certainty) - then I can’t just eat an extra 1,300 calories and still be in a deficit. Likely, I will only be able to eat some fraction of that extra amount, say 600 calories (arbitrary cutoff just for the example).

This has also been something I’ve wondered as well.

My biggest question on this though if there is an elite athlete (cyclist for example) that is way above the Physical Activity Guidelines and on paper they are predicted to be burning many extra Calories for their bodyweight (let’s say like they burn 1500+ extra Calories), what happens if they drop their physical activity by a bit? 30% drop? 40%?

If there is an “upper constraint”, in what way is that affected by a decrease? My prediction would be small decreases in energy expenditure via NEAT overtime after a decrease in that activity that may eventually result in weight gain, but I am very unsure.

Essentially, how would that “upper constraint” affect TDEE, and ostensibly energy balance assuming intake remains the same, following a decrease in physical activity in someone who is well above the physical activity guidelines? Just an interesting question, I understand it’s highly theoretical.

If you are actually burning 1300 kCal, you can consume an 1300 kCal to be at maintenance. To verify this, you’d have to use doubly-labeled water or, in a pinch, indirect calorimetry. In the short term, e.g. a single session, relatively little adaptations will be made.

A few points germane to this discussion:

  1. Calorie estimates for activity are very, very inaccurate
  2. Long-term, the body habituates to a given activity level to result in a similar TDEE. Populations who are very active and very sedentary have about the same TDEE, for example.
  3. Calorie restriction + exercises are still two very important behaviors for weight loss.

What happens to what, exactly?

Ultra-endurance athletes have physical activity levels (PAL) that are far in excess than moderately active and sedentary individuals, where PAL is calculated via TDEE/REE. This usually occurs for relatively short periods of time and isn’t really sustainable long-term, as these individuals lose weight because the human gut cannot actually tolerate enough dietary intake to support weight maintenance, but that’s for another post.

In any case, TDEE does not keep climbing up and up and up- rather it just levels off and other components of the TDEE decrease. When AEE (activity energy expenditure) reduces, other components of TDEE increase.

The upper constraint appears to be an evolutionary adaptation to increase fitness in a population, e.g. the ability to pass on their genes to subsequent generations. NEAT doesn’t tend to be the smoking gun in weight gain (novel) or regain in many individuals, but some folks who are susceptible to gaining excess adiposity…sure.

See above.