Cocoa butter, palm olein and soybean oil in a 16-week diet trial
What it found
In healthy adults, diets rich in cocoa butter, palm olein or soybean oil made no difference to liver fat or belly fat over 16 weeks.
Some blood cholesterol numbers were lower on the soybean oil diet than on the palm olein diet.
What they found
Studies in people
Liver fat
Fat quality did not affect liver fat concentration. This was measured at the start and at week 16.
Belly and body fat
Fat quality did not affect visceral or abdominal subcutaneous fat, or obesity indexes. Body fat mass decreased with soybean oil and cocoa butter compared with palm olein.
Blood cholesterol
Soybean oil lowered total cholesterol, LDL cholesterol and the total cholesterol to HDL ratio compared with palm olein. No diet differences were seen for HDL cholesterol or triglycerides.
Other health measures
Fat quality did not affect blood pressure, liver enzymes, leptin or fasting glucose.
Fecal fatty acids
No diet differences were seen in fecal free fatty acids, except for lower pentadecanoic acid with cocoa butter than with soybean oil and palm olein.
What the authors conclude
“In healthy adults, when consumed as part of eucaloric typical Australian diets, 3 different dietary fat sources did not differentially affect liver fat concentration and amounts of adipose tissue.”
Also in their conclusions
- They conclude that in healthy adults, when consumed as part of eucaloric typical Australian diets, 3 different dietary fat sources did not differentially affect liver fat concentration and amounts of adipose tissue.
- They note that effects on serum lipids were inconsistent across lipid profiles.
- They say the findings must be confirmed in metabolically impaired individuals before recommendations can be made.
How it was done
The authors say the effect of dietary fat quality on liver fat is still unclear. They suggest that inconsistent evidence may be influenced by how saturated the fats are, their chain length, and where they sit within fat molecules.
Eighty-three healthy people aged 20 to 45 with a BMI of 18.5 to 27.5 started the trial and 64 finished it. For 16 weeks they ate the same background diet, differing only in the test fat, which provided 20% of total energy intake, after a 2-week run-in.
What it can’t tell you
- We summarised it from the abstract only.
- This trial was in healthy adults, so the results may not apply to people with metabolic problems.
- It ran for 16 weeks, so it cannot show what longer-term eating patterns would do.
Who paid
- Authors work at
- University of Sydney, Australia; University of Adelaide, Australia
The paper
- Title
- Eucaloric diets enriched in palm olein, cocoa butter, and soybean oil did not differentially affect liver fat concentration in healthy participants: a 16-week randomized controlled trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Stonehouse W, Sergi D, Benassi-Evans B, et al (2021). Eucaloric diets enriched in palm olein, cocoa butter, and soybean oil did not differentially affect liver fat concentration in healthy participants: a 16-week randomized controlled trial. The American journal of clinical nutrition. doi:10.1093/ajcn/nqaa347PubMed 33381795DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error