The aim of the study is to examine whether lean fish, fatty fish, and camelina sativa oil (CSO) a plant‐based source of alpha‐linolenic acid (ALA), differ in their metabolic effects in subjects with impaired glucose metabolism. Altogether 79 volunteers with impaired fasting glucose, BMI 25–36 kg m–2, age 43–72 years, participated in a 12‐week randomized controlled trial with four parallel groups, that is, the FF (four fish meals/week), LF (four fish meals/week), CSO (10 g d–1 ALA), and control (limited intakes of fish and sources of ALA) groups. The proportions of eicosapentaenoic acid and DHA increase in plasma lipids in the FF group, and the proportion of ALA increase in the CSO group (p < 0.0001 for all). In the CSO group, total and LDL‐cholesterol (C) concentrations decrease compared with the FF and LF groups; LDL‐C/HDL‐C and ApoB/ApoA‐I ratios decrease compared with the LF group. There are no significant changes in glucose metabolism or markers of low‐grade inflammation. The study concluded that a diet enriched in CSO improves serum lipid profile as compared with a diet enriched in FF or LF in subjects with impaired fasting glucose, with no differences in glucose metabolism or concentrations of inflammatory markers.