Dietary Fat

AvoidCaution

4 studies · 2 recommendations

Last updated: February 25, 2026

Avoid1 studies

High-fat diets linked to increased breast cancer risk

A case-control study comparing breast cancer patients with matched controls found significant differences in high-fat diet consumption between the two groups, suggesting that high dietary fat intake is associated with elevated breast cancer risk.

Evidence

The Relationship between Breast Cancer and Lifestyle based on Cockerham and Bourdieu Theory: a study on Kerman women

Authors: Amiri-Moghaddam, Marjan, Ghadimi, Bahram, PourRanjbar, Muhammad

Published: January 1, 2016

In a case-control study of 260 women with breast cancer and 260 age- and residence-matched controls in Kerman, a statistically significant difference was observed between the two groups in use of high-fat diet (p < 0.05, chi-square test). The cases demonstrated higher consumption of high-fat foods compared to the control group, supporting the association between high dietary fat intake and breast cancer risk.

View Source →

Caution3 studies

Reducing dietary fat intake below 25% of calories may lower breast cancer recurrence risk

Three studies involving over 178 participants link high dietary fat consumption to breast cancer risk and recurrence. A consensus statement identified breast cancer among 7 cancer types potentially related to fat intake, noting populations deriving 43% of energy from fat face elevated risk, though whether total fat or specific fatty acid types drive the association remains unresolved. Two RCTs tested fat-reduction interventions in breast cancer survivors and high-risk individuals. One 24-week trial targeted reducing fat to 25% of total calories alongside increased fruit, vegetable, and fiber intake, monitoring estrogen status and inflammatory markers tied to recurrence. A second 12-week RCT in 78 overweight individuals with family history of breast cancer achieved favorable fat-intake reductions, with 36% of the intervention group reaching 5% weight loss versus 0% of controls. Limiting dietary fat — particularly saturated sources — while maintaining adequate nutrition represents a reasonable precautionary measure.

Evidence

Feasibility study to assess the impact of a lifestyle intervention (‘LivingWELL’) in people having an assessment of their family history of colorectal or breast cancer

Authors: Anderson, Annie S., Berg, Jonathan, Dunlop, Jacqueline, Gallant, Stephanie, Macleod, Maureen, Miedzybrodska, Zosia, Mutrie, Nanette, O’Carroll, Ronan E., Stead, Martine, Steele, Robert J. C., Taylor, Rod S., Vinnicombe, Sarah

Published: February 1, 2018

This RCT randomized 78 overweight individuals (BMI ≥25 kg/m²) with a family history of breast or colorectal cancer to a 12-week lifestyle intervention or control. The intervention group received personalized dietary counselling targeting fat reduction alongside physical activity support. Favourable reductions in dietary fat intake were reported in the intervention arm. Overall, 36% of intervention participants achieved 5% weight loss compared to 0% of controls, with questionnaire completion rates exceeding 98%.

View Source →

Study protocol to investigate the effect of a lifestyle intervention on body weight, psychological health status and risk factors associated with disease recurrence in women recovering from breast cancer treatment

Authors: A Campbell, A McTiernan, A McTiernan, A Silvestri, A Visser, AB Kornblith, AC Utter, AH Wu, AJ Daley, Amanda Daley, AN Dentino, AS Fairey, AT Beck, B Dugue, B Rockhill, B Zumoff, BL Andersen, BL Gruber, BL Stauffer, BM Pinto, BS McEwen, C Peters, C Peters, C Wiltschke, CB Ebbeling, CL Caldwell, CM Bryla, CM Friedenreich, D Geffken, D Nerozzi, DC McMillan, DC Nieman, DC Nieman, DC Nieman, DC Nieman, DC Nieman, DC Nieman, DF Cella, DG Cruess, DH Bovbjerg, DM Golden-Kreutz, DV Schapira, DW Kissane, E Maunsell, EA Bermudez, G Borg, G van der Pompe, G van der Pompe, GG Kolden, H Davis, H Kervinen, HC Abercrombie, Helen Crank, Hilary Powers, HV Thomas, J Gallagher, J Kaukua, J Verloop, JA Cauley, JE Bower, JE Epping-Jordan, JF Sallis, JK Camoriano, JK Smith, JO Prochaska, John M Saxton, JR Calabrese, JS Goodwin, KL Jen, KM Rexrode, KS Courneya, KS Madden, L Bernstein, L Chang, M Maes, M Maes, M Maes, M Mezzetti, MD Gammon, MD Holmes, MD Holmes, ME Nelson, MK Baldwin, N Banu, Nanette Mutrie, Nicola Woodroofe, PJ Goodwin, RJ Benschop, Robert Coleman, RT Chlebowski, S Cohen, S Levy, S Yamasaki, SE Hankinson, SE Sephton, SI Mannering, SJ Schleifer, SJH Biddle, SK Lutgendorf, SM Levy, T Moradi, T Treasure, TA Wadden, TP Erlinger, U Ehlert, Vanessa Siddall, Y Touitou, Y Touitou, Z Djuric, Z Kronfol

Published: January 1, 2006

This randomized controlled trial of 100 breast cancer survivors implements a dietary intervention that aims to reduce fat intake to approximately 25% of total calories. The dietary strategy also includes consuming at least 5 portions of fruit and vegetables daily, increasing fiber intake, reducing refined carbohydrates, and moderating alcohol consumption. The trial monitors biomarkers associated with disease recurrence including estrogen status, inflammatory markers, and immune function indices over a 24-week intervention period.

View Source →

Report from the working group on diet and cancer.

Authors: Adami, Hans-Olov, Dragsted, Lars, Enig, Bent, Hansen, Jens, Haraldsdóttir, Jóhanna, Hill, Michael J., Holm, Lars Erik, Knudsen, Ib, Larsen, Jens-Jorgen, Lutz, Werner K., Osler, Merete, Overvad, Kim, Sabroe, Svend, Sanner, Tore, Sorensen, Thorkild I. A., Strube, Michael, Thorling, Eivind B.

Published: January 1, 1993

The consensus identified 7 cancer types potentially related to fat consumption: breast, colon, rectum, endometrium, ovary, prostate, and gall bladder. The Danish population obtains 43% of energy from fat, with a steadily increasing trend over 30 years, primarily from margarine and butter. Whether the relationship between fat and breast cancer is causal, and whether it depends on total fat or specific fatty acid types (saturated, monounsaturated, polyunsaturated), remains far from clear and may vary between fat-related cancer types. The 1991 ECP meeting showed a general trend to weaken earlier 1985 statements regarding fat. Reduction in fat intake was noted to likely increase levels of water-soluble vitamins.

View Source →