Calorie Compensation: Does the Body Compensate for Training?

Older women who'd already completed 16 weeks of combined aerobic and resistance training continued for another 16 weeks. Groups continued to train at a low, moderate, or high frequency. Strength kept climbing in every group, but what happened to the calories they burned outside the gym told a more interesting story, especially for those training at the highest frequency. Does more training always mean more total energy expenditure? Let's take a look.

Overview

• What did they test? Fifty-seven previously sedentary women aged 60 to 74 continued a combined aerobic and resistance training program from week 16 through to week 32, having been randomized at the outset to train at a low, moderate, or high frequency. Strength, body composition, aerobic fitness, inflammatory markers, mood, and several components of daily energy expenditure, including non-exercise activity thermogenesis (NEAT), were assessed at both time points.
• What did they find? Strength improved for all groups, while body composition, fitness, and inflammatory markers stayed largely unchanged. Depression scores were lower in the highest-frequency group than the moderate-frequency group. Training-related energy expenditure increased significantly over time, but NEAT increased in the high-frequency group, fell in the moderate-frequency group, and remained similar in the low-frequency group.
• What does it mean for you? For older women (or coaches working with them) deciding how often to train, this study found similar strength and aerobic fitness outcomes across groups, and no clear energy expenditure case for training more often. So frequency is probably better chosen based on what fits your schedule and recovery than on chasing extra calorie burn.

What’s the Problem?

According to the constrained energy expenditure model, the body can compensate for structured activity (i.e., training) by quietly reducing energy expenditure elsewhere, often through non-exercise activity thermogenesis (NEAT), the energy we burn through incidental movement like walking, fidgeting, or standing 1. 

The authors of the study we are reviewing here had previously found that, across the first 16 weeks of a combined aerobic and resistance training program, this kind of compensation played out differently depending on how often older women had trained 2. NEAT rose in the moderate-frequency group, trended upward in the low-frequency group, and fell in the high-frequency group, while total energy expenditure only increased in the moderate-frequency group, remaining similar in the other two.

They thought the decline in NEAT was more about the time commitment of six weekly sessions (three aerobic and three resistance) than physical fatigue, since physical performance increased and markers of overtraining stress didn't support a fatigue-based explanation. What wasn't clear was whether this pattern would continue to hold up over a longer period.

Purpose

This study aimed to investigate how differing frequencies of late-stage (16 to 32 weeks) combined aerobic and resistance training affected body composition, energy expenditure, strength, aerobic fitness, inflammation, and mood.

Hypothesis

The authors hypothesized that most measures would show little to no change, with one exception: they expected training-related energy expenditure to keep increasing over time across all groups, while non-exercise activity thermogenesis (NEAT) would follow different patterns depending on the training group.

What Did They Test and How?

Participants

This study included 57 healthy but previously sedentary older women (60–74 years) who continued training after an initial 16 weeks of combined aerobic and resistance training. 2 Participants had to be free of metabolic disorders and not be taking medications with known effects on energy expenditure. By training group, at the start of this study (after 16 weeks of training), characteristics were: