Effect of dietary fatty acid composition on substrate utilization and body weight maintenance in humans

Eur J Nutr. 2014 Apr;53(3):691-710. doi: 10.1007/s00394-013-0638-z. Epub 2013 Dec 22.


Background/purpose: Dietary fat content is a primary factor associated with the increase in global obesity rates. There is a delay in achieving fat balance following exposure to a high-fat (HF) diet (≥ 40% of total energy from fat) and fat balance is closely linked to energy balance. Exercise has been shown to improve this rate of adaptation to a HF diet. Recently, however, the role of dietary fatty acid composition on energy and macronutrient balance has come into question.

Methods: We chose studies that compared monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and saturated fatty acids (SFA). We have reviewed studies that measured diet-induced thermogenesis (DIT), energy expenditure (EE), or fat oxidation (FOx) in response to a HF meal challenge, or long-term dietary intervention comparing these fatty acids.

Results: While single-meal studies show that SFA induce lower DIT and FOx compared to unsaturated fats, the effect of the degree of unsaturation (MUFA vs. PUFA) appears to yet be determined. Long-term dietary interventions also support the notion that unsaturated fats induce greater EE, DIT, and/or FOx versus SFA and that a high MUFA diet induces more weight loss compared to a high SFA diet. Sex and BMI status also affect the metabolic responses to different fatty acids; however, more research in these areas is warranted.

Conclusion: SFA are likely more obesigenic than MUFA, and PUFA. The unsaturated fats appear to be more metabolically beneficial, specifically MUFA ≥ PUFA > SFA, as evidenced by the higher DIT and FOx following HF meals or diets.

Publication types

  • Comparative Study
  • Review

MeSH terms

  • Adaptation, Physiological
  • Diet, High-Fat / adverse effects*
  • Dietary Fats / adverse effects*
  • Dietary Fats / metabolism
  • Energy Metabolism*
  • Exercise
  • Fatty Acids / adverse effects*
  • Fatty Acids / metabolism
  • Fatty Acids, Monounsaturated / adverse effects
  • Fatty Acids, Monounsaturated / metabolism
  • Fatty Acids, Unsaturated / adverse effects
  • Fatty Acids, Unsaturated / metabolism
  • Humans
  • Obesity / etiology*
  • Obesity / metabolism
  • Overweight / etiology*
  • Overweight / metabolism
  • Oxidation-Reduction
  • Thermogenesis
  • Weight Gain


  • Dietary Fats
  • Fatty Acids
  • Fatty Acids, Monounsaturated
  • Fatty Acids, Unsaturated