## 2 Materials and Methods
### Procedures  
Indirect calorimetry was used to measure mREE (V2 mask ([PERSON], KS, USA), Quark CPET ([PERSON], [PERSON], Rome, Italy), with Quark 8.1 PC software support). The measurement for mREE was performed in a thermoneutral environment, in silence, between 6.00 and 9.00 a.m., after 12 h of fasting [16]. The last 20 min of the 30 min measurement was used [17]. During every measurement, RQ was monitored to detect any possible protocol violations or inaccurate gas measurements [17]. pREE was calculated with the Harris-Benedict equation [18]. This is the most commonly used equation when calculating the mREE/pREE ratio in athletes, and it has previously been used in similar study designs [8; 19]. The Weir equation was also used [20; 21]. All cyclists filled in the LEAF questionnaire. Based on the LEAF questionnaire, they were put in the LEAF- group (no positive answers) or in the LEAF+ group (1 or more positive answers).  
The next day, participants were given an accelerometer (ActiGraph GT3X(r), Pensacola, FL, USA) that is worn on the left hip at all times except for training. This was used to obtain energy expenditure (EE) and nonexercise activity thermogenesis (NEAT) data. During intentional physical activity, the heart rate (HR) was monitored with Polar HR monitors (Polar V800, Polar Electro, Kempele, Finland) to measure EEE. Energy intake (EI) was calculated by participants filling in the diary log. As the calculation of EA is a challenging task for the participants and the scientists, this research followed recommendations by [PERSON] et al. [22] and included only subjects who successfully completed all records. They were given specific instructions on how to measure (by taking photographic evidence, using measuring scales, and weighing foods) and record all foods and liquids ingested. EI data was analyzed with Foodworks 9 Professional Edition (version 9.0.3973, Xyrix Software, Brisbane, Queensland, Australia) by an experienced nutritionist.  
On the fifth day, incremental testing took place with indirect calorimetry. A Cyclus 2 ergometer was used for incremental testing (Cyclus 2, Leipzig, Germany). Following 20 min of warm-up, participants started the ramp test at 60 W, with an additional 15 W every min. The test was performed until volitional exhaustion. The ambient temperature in the laboratory was 21 \({}^{\circ}\)C. Lactate was sampled from the earlobe. Samples were obtained at rest before any physical activities, at the end of the test, and 5 min after the test. Lactate was analyzed with the blood lactate analyzer Biosen C_Line (EKF Diagnostics, Germany).  
WDEB was calculated as WDEB = EI - (EEE + EPOC + DIT + NEAT + mREE) for every h [12] (where EPOC is excess postexercise oxygen consumption, DIT is diet-indices thermogenesis and NEAT). As previously described, EEE was measured by an HR monitor. In the first h after exercise, EPOC was defined as 5% of EEE and the second hour as 3% of EEE [23]. DIT is 10% of EI. In the sixth hour, after all meals were used to calculate DIT with the equation DIT = 175.9 x t x e\({}^{-t/1.3}\), where \(t\) is time [23], NEAT was measured by an accelerometer.  
For all participants, we calculated WDEB\({}_{\text{neg}}\), which is time spent in negative energy balance, and WDEB\({}_{\text{-300}}\), which is time spend in energy balance under \(-\)300 kcal. EA was calculated as EA = (EI - EEE)/FFM. An example of WDEB\({}_{\text{neg}}\) and WDEB\({}_{\text{-300}}\) calculation can be seen in Figure 1.