A number of custom OpenSource diet formulations have been widely published and have become the standards for many diet-induced disease models. These custom diets are kept in-stock in pelleted form and ready for shipment. Our in-stock custom diets provide a clean, open formula background in which to make modifications. See our custom diets page for more information on other custom formulations.
Research Diets, Inc. is well known as the gold standard in high-fat diets for diet-induced obesity research worldwide. Below are the most widely published diets for these studies. All high-fat diets are not the same. We have made hundreds of modifications to these formulas to meet individual researcher needs. Please consult with one of our scientists before choosing a high-fat diet for your next study. Read more.
Methionine and Choline Deficient (MCD) DietsAmong the different approaches for diet-induced NAFLD in rodents, MCD diets produce the most severe NASH phenotype in the shortest timeframe. MCD diets are formulated with the replacement of whole protein (such as casein) in purified diets with crystalline amino acids and the removal of both methionine and choline. Read more
Choline Deficient (CD) DietsTypically, CD diets used in fatty liver disease studies tend to contain higher levels of fat (45-60 kcal%) and these diets can induce steatosis, inflammation and fibrosis without the reduction in body weight typically found when feeding MCD diets, making CD diets more appealing to some researchers. Read more
Pellizzon and Ricci , The common use of improper control diets in diet-induced metabolic disease research confounds data interpretation: the fiber factor. Nutrition & Metabolism (2018) 15:3. Download publication
It's important to note that calorie-restriction regimens are not starvation diets. The weight loss achieved with calorie restriction in the CALERIE trial resulted in body weights within the normal or overweight range.
Most research to date has focused on the weight-loss aspect of fasting, primarily in obese people, and only a few small clinical trials have been conducted. More work is needed to determine which, if any, types of fasting diets have long-term benefits.
In the coming years, researchers will continue to explore many unresolved questions. What are the long-term benefits and risks of the various eating patterns? Which diets are feasible as a long-term practice? What specific biological effects on aging and disease are triggered by a particular eating pattern? If a specific way of eating is recommended, at what age is it best to start, and is it safe to continue as you get older?
We will review your pet's medical and diet history, evaluate his or her current diet, discuss appropriate feeding strategies for your pet, answer your nutrition questions and provide written recommendations to you and your veterinarian for commercial diets, treats and supplements (if applicable) to meet your pet's individual nutritional needs.
The feeding of RMBDs to dogs and cats has received increasing attention in recent years. The American Animal Hospital Association,1 AVMA,2 and Canadian Veterinary Medical Association3 have adopted statements discouraging the inclusion of raw or undercooked animal-source protein in dog and cat diets. The Delta Society's Pet Partners Program expressed concern that pets in a therapy animal program could be shedding pathogens in the presence of immunocompromised humans and other at-risk human populations. Therefore, they adopted in 2010 a policy that precludes animals that eat RMBDs from participating in their therapy animal program.4 For each of the organizations, the primary reason indicated to oppose feeding of an RMBD was that potential pathogen contamination of the uncooked meat causes health risks to the pet fed the diet as well as to other pets, human family members, and members of the public in contact with the pet. These statements did not address other potential problems of RMBDs, such as potential nutritional imbalances or other safety issues of the diets (eg, feeding bones); they also did not address the reasons people want to feed these diets or potential benefits of this type of diet.
The intent of the information reported here is to provide a balanced review of the issue of feeding RMBDs, types of RMBDs, reasons these diets are fed, and potential benefits and risks associated with feeding of RMBDs. The information will also highlight areas in which additional research is needed to better delineate benefits and risks.
The most common forms of commercial RMBDs are fresh, frozen, and freeze-dried diets intended to be nutritionally complete and balanced. These diets are often formulated to meet values listed in the AAFCO Dog or Cat Food Nutrient Profiles, and individual diets may meet values listed for adult maintenance, growth and gestation-lactation, or all life stages. However, some of these foods may be labeled as intended for intermittent or supplemental feeding only, which means that they are not nutritionally complete and balanced. Commercial RMBDs typically are created from recipes developed by or for a company marketing a specific brand of pet food; these commercial RMBDs are made in large quantities in pet food manufacturing facilities or industrial kitchens, then packaged into smaller volumes for purchase and feeding by pet owners. In addition to the fresh, frozen, and freeze-dried commercial diets, another less common form of RMBD is a carbohydrate premix that includes grains, vitamins, and minerals and is intended to have a raw meat protein source added by the pet owner to provide a complete diet.
Proponents of feeding commercial or home-prepared RMBDs often claim nutritional superiority of these diets and important health benefits. Many claims of benefits are largely unproven and not based on scientific evidence, but they appear plausible to well-intending pet owners who want to feed a diet that will optimize health and wellness of their pets. Anecdotal benefits for RMBDs include better palatability of these diets, cleaner teeth from chewing bones as a part of these diets, a shiny coat, and owner perception that they are providing their pet with a more natural diet.
A founding premise in popular lay publications and on the Internet regarding RMBDs is that these are the diets that wild, nondomesticated dog and cat species ate during their evolution into pets, which may provide an important rationale for some owners to feed these diets to their dogs and cats.7,8 Cats have remained obligate carnivores during domestication, and their natural diet includes a range of small prey species such as mammals, reptiles, birds, and insects that can be hunted, captured, and eaten by the cats. Conversely, dogs have adapted to eating an omnivorous diet and can consume a variety of plant and animal products to meet their essential nutrient requirements. However, both cats and dogs are able to digest and metabolize many nutrients provided from plant-based ingredients.15 Additionally, dogs have undergone an incredible variety of selection pressures resulting in large phenotypic differences from their ancestors and among current breeds.16,17 In fact, it was reported18 that there are 36 regions of the genome that differ between dogs and wolves, 10 of which play a critical role in starch digestion and fat metabolism. The authors of that study18 conclude that these genetic differences in the genome between dogs and wolves and hence the ability to digest starch and fat constituted a crucial step in the early domestication of dogs. Therefore, even if the typical diet eaten by a wild, nondomesticated dog or cat can be considered optimal for reproduction and survival in those animals, in which the lifespan is typically quite short, these diets may not be optimal for domestic dogs and cats living in a home environment, with owners who anticipate that their pets will have long and healthy lives.
Another frequently cited benefit when feeding RMBDs is an improvement in immune function. In experiments conducted by one of the authors (BAH), domestic cats fed an RMBD for 10 weeks had a significant increase in lymphocyte and immunoglobulin production, whereas there were no significant changes over the study period for cats fed a cooked commercial moist diet. In those experiments, it was also found that cats fed the RMBD were fecal shedders of Salmonella spp. Higher amounts of exposure to microbes and microbial degradation products, exposure to pathogens, changes in intestinal microflora, or nutritional differences in the diets may have stimulated the immune response detected for cats fed the RMBD. However, potential health benefits and effects of long-term feeding of RMBDs have not been critically evaluated.
Although there is evidence for improved digestibility of proteins in RMBDs, compared with digestibility of proteins in extruded diets, the clinical effects of this difference are unclear and require further study. Effects of processing for some commercial RMBDs (eg, freeze-dried or carbohydrate premixes) are also not fully understood. In addition, one of the potential effects attributable to differences in processing is an alteration of the gastrointestinal microbiome. Research is needed on differences in the gastrointestinal biome between dogs and cats that are fed RMBDs versus extruded foods (and compared with results for dogs and cats fed home-cooked diets and canned diets as well as effects among various types of RMBDs). The function and role of chronic exposure to bacteria in metabolism and immune function also should be the focus of future studies.
Proponents of home-prepared diets, including RMBDs, often cite recalls of commercially available dry extruded and moist diets because of bacterial and chemical contamination as a reason that pets should not be fed those types of diets. Contamination of some commercial pet foods with melamine-cyanuric acid in 2007 resulted in dogs and cats with acute kidney injury.71 That episode was caused by the supplier deliberately adulterating a human-grade food ingredient that was also used in pet food. In response, in part, to this tragedy, the FDA Amendments Act of 2007 was passed to strengthen the food recall process, and food safety legislation has been further strengthened by the FDA Food Safety Modernization Act that went into effect in 2012.72 A recall is a method of removing or correcting consumer products that are in violation of regulations administered by the FDA. Although those pieces of legislation grant the FDA mandatory authority to initiate a recall in the future, recalls of pet food currently are initiated voluntarily by a pet food manufacturer, although the FDA can request a manufacturer to initiate a recall. The FDA Amendments Act of 2007 requires that manufacturers submit a report to the FDA no later than 24 hours after determining that there is a reasonable probability that the use of or exposure to the food will cause serious adverse health consequences to or the death of animals (or humans), which constitutes a potential class 1 recall.71,72 041b061a72