Introduction
Obesity is one of the most common health problems affecting dogs today. An estimated 60% of dogs are overweight or obese. This excess weight puts dogs at risk for many health issues like diabetes, heart disease, and arthritis. Successfully helping dogs lose weight is important for their health and wellbeing.
When dogs are put on a low-calorie diet for weight loss, there are several metabolic and hormonal changes that occur in their bodies to promote fat burning and weight loss. Understanding the physiology of how reduced-calorie diets work in dogs can help owners better manage their pet's weight loss regimen. This article will discuss how low-calorie diets affect fat metabolism, hormone levels, and energy balance in the body to result in weight loss for overweight dogs.
Calorie Reduction for Weight Loss
The most basic way low-calorie diets help dogs lose weight is by simply reducing their caloric intake below the level needed to maintain their current body weight. Just like humans, when dogs consume fewer calories than they burn, their bodies tap into fat stores for energy. The excess calories from fat that is broken down results in weight loss over time.
The first step of any canine weight loss program is calculating the dog's current resting energy requirement (RER). Factors like the dog's ideal weight, current weight, age, sex, neuter status, and activity level are used to estimate RER. Once current calories for maintenance are known, the dog's daily calories can be reduced by 10-20% below the maintenance level to spur weight loss. As weight loss occurs, the RER will be recalculated periodically since as body mass decreases, so does caloric need.
Metabolic Adaptations
When calorie reduction happens, a dog's body makes several metabolic adaptations to the perceived "starvation" state. The main adaptation is a reduction in resting metabolic rate. Total RMR decreases because the dog has less body tissue after losing weight. Lean body mass is reduced along with fat mass when weight loss happens. With less lean tissue, the dog's overall metabolic workload decreases.
Research on metabolic adaptations during weight loss in dogs is limited, but available evidence suggests their RMR decreases by about 30%. In one study, RMR decreased from 1,418 to 1,027 calories per day after dogs lost an average of 22% of their body weight over 3 months. This shows that continued calorie reduction is necessary for dogs to keep losing weight. Their lowered RMR means fewer calories are actually needed after the initial weight loss phase.
Changes in Fat Metabolism
When excessive calories are reduced, the body must tap into other energy stores like fat to make up the difference. Fat from adipose tissue provides the majority of energy during weight loss in dogs. The fat is broken down through lipolysis and beta-oxidation into fatty acids that can enter the Krebs cycle to generate ATP energy.
Studies show that overweight dogs have dysregulated fat metabolism that improves with weight loss. Fat breakdown and synthesis become more balanced as excess fat stores shrink. Signals of energy deficit activate lipolytic pathways while reduced levels of the hormone insulin allow greater Fatty acid release from adipocytes. Enzymes like HSL, ATGL, and CPT1 become more active in adipose tissue to ramp up fat breakdown.
Increase in Lipid Oxidation
While enhanced lipolysis releases more fatty acids, increased lipid oxidation actually burns the fatty acids for energy. The body adapts during weight loss to use fat as the primary fuel source. Molecular switches like PGC-1a activate the genes involved in fat oxidation. Mitochondrial function improves and more enzymes like CPT1 are produced to transport fatty acids into mitochondria for oxidation. Research in obese dogs found that a weight loss diet for 28 days increased fat oxidation rates by 29%. This switch towards fat burning rather than carbohydrate metabolism facilitates weight loss.
Changes in Adipokines and Appetite Hormones
The adipose tissue itself functions as an endocrine organ by releasing hormones and signals involved in energy regulation. Key hormones affected by weight loss include leptin, adiponectin, ghrelin, and peptide YY. Leptin is a satiety hormone released from fat cells that decreases appetite. Dogs losing weight show a significant reduction in circulating leptin levels. This leptin decline signals the hypothalamus that the body is in a starvation state, which increases hunger.
Researchers believe the drop in leptin accompanying weight loss is a key reason it is difficult for dogs to maintain their reduced body weight. However, other hormones like adiponectin and peptide YY increase with weight loss in dogs. These hormones help suppress appetite and enhance fat oxidation. The net effects of all appetite and metabolism related hormones likely promote weight loss, although leptin declines initially increase hunger.
Homemade Low-Calorie Dog Treats for Weight Loss
When implementing a weight loss plan for dogs, treats and chews make up an important part of the total calorie intake that must be controlled. While commercial low-calorie dog treats are available, making homemade low-calorie treats allows for total ingredients and nutrition control. Homemade treats are often lower in calories and higher in nutrients compared to many commercial options. Owners can adjust ingredients to create treats customized to their individual dog's needs and preferences. Fortunately, we have a list of recipes for low-calorie homemade dog treats for owners to try.
Some key strategies help reduce calories in homemade dog treats. Using lean proteins like chicken, fish, or egg whites provides protein without as much fat. Substituting lower calorie vegetables like carrots or green beans in place of ingredients like corn or wheat helps reduce calories. Avoiding added sugars or using sugar substitutes also lowers caloric density. Choosing healthier fats like olive oil or coconut oil instead of butter lowers saturated fat. Portion control is key for homemade treats just as it is for main meals. Owners should calculate calories for weight loss treats and adjust recipes or portions accordingly.
Three specific recipes for homemade dog treats that can aid weight loss include:
- Sweet Potato Chews – Dehydrated sweet potato slices offer nutritious fiber and vitamins.
- Chicken and Green Bean Treats – Lean chicken and crunchy green beans baked into bite-sized treats.
- Egg White Pups – Whipped egg whites poured into silicone molds and baked provide protein without fat and few calories.
In addition to the treat recipes themselves, using some preparation methods can further reduce calorie content. Baking or dehydrating treats removes excess fat and calories from frying. Using silicone molds to shape treats into small portioned sizes allows accurate calorie tracking. Cutting treats into little bites prevents overconsumption from large or high-calorie treats. Adding vegetable or fruit purees to treats adds low-calorie bulk and nutrients.
Making treats at home allows owner creativity in crafting personalized recipes dogs love that also support weight loss goals. Rotating different flavor recipes keeps dogs interested without overconsuming the same treats. Used alongside a complete reduced-calorie dog food, homemade treats help overweight dogs lose weight without feeling deprived.
Increased Physical Activity
While diet is the most important factor for weight loss in dogs, moderate increases in physical activity can augment fat burning and cause greater calorie expenditure. Exercise helps maintain or increase lean muscle mass, which raises BMR. Various studies have shown higher weight loss in dogs when their exercise is increased along with feeding a reduced-calorie diet.
Physical activity is especially important at the maintenance phase once target weight has been reached. Keeping activity levels elevated helps prevent metabolic rate declines that often accompany weight loss. Exercise also continues to burn extra calories that would otherwise be stored as fat. However, exercise alone without adjusting a dog's food intake is not an effective weight loss strategy.
The primary takeaway is that a successful canine weight loss program requires cutting back calories consumed along with gently increasing a dog's physical activity. This two-pronged approach provides the greatest chance for significant fat loss and achieving a healthy body condition.
Monitoring Progress
Ideally, dogs should lose about 1-2% of their body weight per week. Losing weight any faster risks health issues. Owners should monitor their dog's weight weekly or biweekly to make sure the diet is providing the intended steady weight loss. The dog's RER can be adjusted down further if weight loss stalls.
Veterinarians may recommend laboratory tests to monitor the dog's health during weight loss. Tests like those measuring serum chemistry, urinalysis, cholesterol, and thyroid levels help ensure the weight reduction diet is not negatively affecting organ function or metabolism. Monitoring body condition score along with body weight also assists with determining optimal progress of fat reduction.
Weight Maintenance After Loss
Unfortunately, most dogs eventually regain much of the weight they worked so hard to lose. To keep the pounds off after successfully slimming down, dogs need permanent lifestyle changes. Feeding an ongoing calorie-controlled diet is imperative. Owners must resist the urge to reward weight loss by returning to free-choice feeding.
Weight maintenance diets usually provide 20% fewer calories than pre-weight loss maintenance diets. Foods with higher protein and fiber content help dogs feel fuller. Adding low-calorie bulk like green beans or pumpkin provides volume without excess calories. Continued daily exercise keeps energy expenditure elevated. Weighing dogs weekly lets owners quickly intervene if regaining occurs.
Maintaining a reduced body weight long-term requires constant diligence and resisting the temptation to overfeed. But keeping obesity away contributes greatly to lifelong health, mobility, and quality of life for dogs.
