Both Omega 3 and calorie restriction have been suggested to have a role inhibiting cancers.
Here mice that over-express HER2 were allowed to eat as much as they wanted (AL), or calorie restricted. Some were fed with an omega 6 rich oil (soy oil which contains some plant based Omega 3 unlike many other vegetable oils) as their main fat and others with the Omega 3 EPA as their main fat.
The eat all you like high Omega 6 mice 
had an 87% tumor incidence, and the intermittently calorie restricted with a high Omega 3 EPA intake had a 15% tumor incidence, which is thought provoking 
as well as supporting the general contention of this thread.
It is interesting that intermittent calorie restriction was more effective than chronic restriction, which raises a lot of questions.
It would be interesting to know the original dietary content of the mice and their fat tissue compositions prior to the experiment; I have not seen the full paper.
As previously discussed on the separate but related topic of ketogenic diets for cancer, it is also likely that outcomes will depend on the type of fat consumed.
control (Con) ad libitum (AL),
intermittent calorie-restricted (ICR)
chronic calorie-restricted (CCR)
Cancer Prev Res (Phila). 2013 Jun;6(6):540-7. doi: 10.1158/1940-6207.CAPR-13-0033. Epub 2013 Apr 2.
Combination of intermittent calorie restriction and eicosapentaenoic acid for inhibition of mammary tumors.
Mizuno NK, Rogozina OP, Seppanen CM, Liao DJ, Cleary MP, Grossmann ME.
Author information
Abstract
There are a number of dietary interventions capable of inhibiting mammary tumorigenesis; however, the effectiveness of dietary combinations is largely unexplored. Here, we combined 2 interventions previously shown individually to inhibit mammary tumor development. The first was the use of the omega-3 fatty acid, eicosapentaenoic acid (EPA), and the second was the implementation of calorie restriction. MMTV-Her2/neu mice were used as a model for human breast cancers, which overexpress Her2/neu. Six groups of mice were enrolled. Half were fed a control (Con) diet with 10.1% fat calories from soy oil, whereas the other half consumed a diet with 72% fat calories from EPA. Within each diet, mice were further divided into ad libitum (AL), chronic calorie-restricted (CCR), or intermittent calorie-restricted (ICR) groups.
Mammary tumor incidence was lowest in ICR-EPA (15%) and highest in AL-Con mice (87%), whereas AL-EPA, CCR-Con, CCR-EPA, and ICR-Con groups had mammary tumor incidence rates of 63%, 47%, 40%, and 59%, respectively. Survival was effected similarly by the interventions. Consumption of EPA dramatically reduced serum leptin (P < 0.02) and increased serum adiponectin in the AL-EPA mice compared with AL-Con mice (P < 0.001). Both CCR and ICR decreased serum leptin and insulin-like growth factor I (IGF-I) compared with AL mice but not compared with each other.
These results illustrate that mammary tumor inhibition is significantly increased when ICR and EPA are combined as compared with either intervention alone. This response may be related to alterations in the balance of serum growth factors and adipokines.
Hybrid Mode
