I don't use 3dLME myself as I generally code up my own, but I would have thought that you would need a
+ in your formulae:
-gltLabel 1 'HF-NF' -gltCode 1 'Task : 1*HiFat -1*NonFood ' \
-gltLabel 2 'LF-NF' -gltCode 2 'Task : 1*LowFat -1*NonFood ' \
-gltLabel 3 'HF-LF' -gltCode 3 'Task : 1*HiFat -1*LowFat ' \
-gltLabel 4 'AllFood-NF' -gltCode 4 'Task : 0.5*HiFat
+0.5*LowFat -1*NonFood' \
-gltLabel 5 'Eugly_AllFood-NF' -gltCode 5 'Task : 0.5*HiFat
+0.5*LowFat -1*NonFood Group : 1*Eugly' \
-gltLabel 6 'Sal_AllFood-NF' -gltCode 6 'Task : 0.5*HiFat +0.5*LowFat -1*NonFood Group : 1*Saline'