▁a ▁low - f at ▁plant - based ▁di et ▁found ▁that ▁the ▁average ▁particip ant ▁lost ▁ ▁over ▁four teen ▁weeks , ▁and ▁attributed ▁the ▁weight ▁loss ▁to ▁the ▁reduced ▁energy ▁density ▁of ▁the ▁food s ▁resulting ▁from ▁their ▁low ▁fat ▁content ▁and ▁high ▁fi ber ▁content , ▁and ▁the ▁increased ▁therm ic ▁effect . ▁Nevertheless , ▁these ▁di ets ▁are ▁not ▁" negative - cal orie " ▁since ▁they ▁bear ▁energy . ▁Another ▁study ▁demonstrated ▁that ▁negative - cal orie ▁di ets ▁( N CD s ) ▁have ▁the ▁same ▁effic acy ▁to ▁low - cal orie ▁di ets ▁( L CD s ) ▁in ▁indu cing ▁weight ▁loss ▁when ▁both ▁of ▁these ▁di ets ▁are ▁combined ▁with ▁exercise . ▁ ▁Che wing ▁g um ▁was ▁once ▁spec ulated ▁as ▁" negative - cal orie ▁food ," ▁however ▁a ▁study ▁on ▁che wing ▁g um ▁reported ▁m astic ation ▁burn s ▁roughly ▁ ▁per ▁hour . ▁Therefore , ▁one ▁stick ▁of ▁g um ▁which ▁contains ▁around ▁ 1 0 ▁k cal ▁would ▁require ▁being ▁che wed ▁for ▁one ▁or ▁more ▁hours ▁to ▁reach ▁" negative - cal orie ". ▁ ▁See ▁also ▁▁ ▁Diet ▁ ▁Diet ing ▁ ▁Cal orie ▁restriction ▁ ▁List ▁of ▁di ets ▁ ▁Very - low - cal orie ▁di et ▁ ▁F ad ▁di et ▁ ▁Rab bit ▁star v ation ▁ ▁References ▁ ▁Category : P se ud os cience ▁Category : Di ets ▁Category : Met abol ism <0x0A> </s> ▁Pet roph ila ▁sch