v3.25.2
Cover - shares
 6 Months Ended
Jun. 29, 2025
Jul. 28, 2025
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 29, 2025  
Document Transition Report false  
Entity File Number 001-38250  
Entity Registrant Name FAT Brands Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 82-1302696  
Entity Address, Address Line One 9720 Wilshire Blvd.  
Entity Address, Address Line Two Suite 500  
Entity Address, City or Town Beverly Hills  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 90212  
City Area Code (310)  
Local Phone Number 319-1850  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Amendment Flag false  
Document Fiscal Period Focus Q2  
Document Fiscal Year Focus 2025  
Current Fiscal Year End Date --12-28  
Entity Central Index Key 0001705012  
Class A Common Stock    
Document Information [Line Items]    
Title of 12(b) Security Class A Common Stock, par value $0.0001 per share  
Trading Symbol FAT  
Security Exchange Name NASDAQ  
Entity Common Stock, Shares Outstanding   16,614,400
Class B Common Stock    
Document Information [Line Items]    
Title of 12(b) Security Class B Common Stock, par value $0.0001 per share  
Trading Symbol FATBB  
Security Exchange Name NASDAQ  
Entity Common Stock, Shares Outstanding   1,270,805
Series B Cumulative Preferred Stock    
Document Information [Line Items]    
Title of 12(b) Security Series B Cumulative Preferred Stock, par value $0.0001 per share  
Trading Symbol FATBP  
Security Exchange Name NASDAQ