Effects of one week juice fasting on lipid metabolism: a cohort study in healthy subjects

Forsch Komplementarmed Klass Naturheilkd. 2003 Feb;10(1):7-10. doi: 10.1159/000069901.


Objective: We investigated the effects of a popular modified juice fasting program on lipid metabolism.

Volunteers and methods: 5 healthy, nonobese, male volunteers fasted for 8 days. Daily energy intake was limited to 150-300 kcal/d solely as carbohydrates (vegetable and fruit drinks). Physical activity was maintained as before. At baseline, on days 2, 3, and 8 during fasting, and on days 2 and 8 after fasting, serum lipids, lipoproteins, and insulin were investigated.

Results: Juice fasting resulted in bi-phasic changes: Until day 2 and 3 triacylglycerols (TG), very low-density lipoprotein apolipoprotein B (VLDL apo B), and insulin decreased by 52, 51, and 65% respectively, while nonesterified fatty acids (NEFA), low-density lipoprotein (LDL) apo B, and LDL cholesterol increased by 363, 38, and 35%. Between day 3 and 8 NEFA increased; TG and insulin increased as well, but remained below baseline values, and LDL cholesterol normalized. After 8 days juice fasting significant changes (p < 0.05) compared to the baseline were found only for free cholesterol (-10%), phospholipids (-14%), apo AI (-9%), apo AII (-11%), insulin (-42%), C-peptide (-57%), and NEFA (+535%, p = 0.0001). Total cholesterol decreased by 9% (n.s.) after 8 days. One week after the ending of fasting all parameters returned to normal.

Conclusion: Contrary to total fasting and fasting with limited physical activity, 8 days juice fasting without limitation of physical activity results in a decrease of free cholesterol and an only initial increase of LDL cholesterol. After 8 days insulin, TG, and VLDL are still lower than at baseline, however, they have increased compared to the initial phase, probably counterregulatory to a further increase of NEFA.

MeSH terms

  • Adult
  • Apolipoproteins / blood
  • Beverages*
  • Cholesterol / blood
  • Cholesterol, VLDL / blood
  • Cohort Studies
  • Energy Intake
  • Exercise
  • Fasting / blood
  • Fasting / metabolism*
  • Fatty Acids, Nonesterified / blood
  • Fruit*
  • Humans
  • Insulin / blood
  • Ketone Bodies / urine
  • Lipid Metabolism*
  • Lipids / blood
  • Male
  • Triglycerides / blood
  • Vegetables*


  • Apolipoproteins
  • Cholesterol, VLDL
  • Fatty Acids, Nonesterified
  • Insulin
  • Ketone Bodies
  • Lipids
  • Triglycerides
  • Cholesterol