你的失眠、焦慮、憂鬱、腦霧可能來自於熱量吃太少？

 

為了減肥而刻意吃得更少，不只餓肚子，可能也影響你的心理健康。作為身心科醫師，藉由科學證據，一起探索熱量赤字（Caloric Deficit）如何從身體到心理，全面影響情緒、專注力，甚至誘發焦慮或憂鬱。

 

大腦覺得熱量赤字是危機

熱量赤字不只是『少吃多動』這麼簡單。當你長時間吃不夠，大腦會誤以為你正在經歷危機，而啟動壓力系統，不僅會讓你容易焦慮、易怒，甚至影響記憶力和睡眠品質，還可能導致肥胖更難控制。

 

壓力反應系統的長期活化

當身體長期處於熱量不足，會引發持續壓力狀態導致：

• 焦慮增加：經常感到緊張、不安。
• 情緒易怒：容易因小事爆發。
• 思考困難（俗稱腦霧）：專注力和記憶力明顯下降。
• 睡眠惡化：睡不好，更加惡化心理健康。

·         長期壓力賀爾蒙升高還可能增加腹部脂肪囤積，並加劇對高糖高脂食物的渴望，形成惡性循環。

 

內分泌系統的連鎖反應

身體在能量不足時，會犧牲一些『非必要』功能，比如降低新陳代謝、甲狀腺功能（容易疲累、情緒低落）、性荷爾蒙失衡（憂鬱、焦慮、沒精神）。尤其是女性的經期可能混亂，男性則容易感到疲憊、提不起勁。

 

神經傳導物質的失衡

長期吃得太少，會影響大腦控制情緒的化學物質。像是負責快樂的『血清素』變少，會讓人情緒低落，忍不住想吃甜食、澱粉類食物；而『多巴胺』失調，會讓人對食物無法控制地渴望，最終導致暴飲暴食。

 

營養缺乏

節食時很容易忽略營養均衡，如果缺乏維生素B群或微量營養素，情緒問題可能更加嚴重。

熱量赤字與精神疾病

飲食失調（暴食症、厭食症）：從極端的飲食限制，到失控地暴食，形成代償性暴食的惡性循環。

 

創傷後壓力症候群（PTSD）：壓力可能導致亂吃東西或吃太少健康食物，肥胖風險增加。

 

躁鬱症：能量代謝呈現雙相特徵（躁期 ATP 增加，憂鬱期粒線體功能降低）。粒線體功能異常和氧化壓力增加是其核心病理。

 

ADHD：興奮劑可抑制食慾，導致體重下降，但藥效退了，食慾可能反彈。

 

從健康節食到出現飲食障礙，可能沒有想像中的遙遠。當你開始對食物產生強烈的罪惡感，或滿腦子都是食物的想法，這可能不是意志不堅定，而是身體正在警告，已經過度限制飲食。

 

減肥或追求健康不必是一場和自己身體與心靈的戰爭。如果你正因為節食而感到焦慮、疲憊，或被食物的念頭纏繞不去。你的身體正在用這些訊號提醒你：「我需要被照顧」。

 

無論是生理上的營養不足，還是心理上的壓力與焦慮，專業的醫師與心理師能陪伴你一起找到合適的方式，記得找尋自己可以信任的團隊。

 

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