Energy balance
Maintaining energy availability above 30 kcal/kg fat-free mass per day is required to prevent significant reductions in circulating testosterone; deficits below this threshold suppress luteinizing hormone (LH) and subsequently lower testosterone.
If you are training hard and restricting calories, monitor your energy availability. Aim for at least 30 kcal per kg of fat-free mass per day. If you feel fatigued or performance drops, your testosterone may be suppressed by the deficit. Prioritize eating enough to support your training volume before focusing on further fat loss.
Low energy availability is defined as <30 kcal·kg FFM·day−1... These studies clearly indicate the negative effect that low energy availability has on the hypothalamic-pituitary-gonadal axis. Large energy deficits appear to negatively affect testosterone concentrations.
Why this rating
Multiple human studies cited show consistent significant reductions in testosterone with low energy availability, though specific dosing varies.
Source
Manipulation of Dietary Intake on Changes in Circulating Testosterone Concentrations
Amit Zamir et al. · Nutrients · 2021
DOI 10.3390/nu13103375
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