Royal Canin Nutritional Information

Royal Canin Nutritional Information

Focus on: L-carnitine

Obesity Definition and Origins

L-carnitine (sometimes know as vitamin BT) is a water-soluble substance derived from two amino acids, lysine and methionine. It is synthesized in the liver in cats. L-carnitine has a role in energy production in cells.

Dietary sources with the highest content include meat products (50 mg/100 g in beef and 200 mg/100 g in lamb).

Formula

Carnitine exists in two spatial forms – D and L, but only the L form is biologically active. The D form tends to inhibit the action of the L form.

Biological Role

L-carnitine is essential to the molecular system that transports long-chain fatty acids inside the mitochondria, where they are oxidized to produce energy.

Benefits of L-carnitine in Preventing and Treating Obesity in Cats

In obese cats, supplementation of L-carnitine (250 mg PO/12h), combined with a restricted caloric intake (36 kcal/kg of target weight) helped to accelerate weight loss (Center et al., 2000). Cats receiving L-carnitine lost weight faster than cats in the control group: 23.7% in 18 weeks (1.3% per week) compared with 19.6% in the control group (1.0%/week).

Figure 25. Fatty acid transport and the role of carnitine.

Another study examined the potential role of L-carnitine in fat metabolism during the induction of hepatic lipidosis (Blanchard et al., 2002). Spayed female cats received 40 mg/kg of L-carnitine per kg of food (control group) or 1000 mg/kg (study group). The concentration of L-carnitine increased significantly in the plasma, muscles and liver of cats in the study group. In addition, these cats exhibited better protection against the risk of hepatic lipidosis during fasting following obesity. Therefore, L-carnitine has a favorable impact on hepatic metabolism of obese cats.

Success Factors of a Weight Loss Diet for Cats

Obesity is not generally a reason for the consultation, but rather something that is found during the consultation. Many owners do not want to know that their animal is obese, especially when the owner is also overweight. It can be very difficult to convince owners to maintain the animal’s diet if there are no clear visible signs that the cat is losing weight. (© Yves Lanceau (British shorthair)).

Owner Motivation

This is essential. The veterinarian has a very important role to play in convincing owners of the validity of a weight loss diet for overweight cats.

Recommended methods for motivating owners include:

• Getting them to palpate the cat, so they are aware of the fat deposits
• Putting the cat’s excess weight into human terms (in equivalent weight); e.g., a cat that is 40% overweight is the same as a 165-pound man actually weighing over 230 pounds!
• Providing information on the following:

• The health problems caused by excess weight
• The benefits of a diet in terms of mobility and coat, etc.
• The importance of the owner’s involvement in the success of the animal’s diet

The Choice of Food and How It Is Given

Caloric intake will have to be reduced, but there are rules that need to be followed.

USE ONLY low energy food in the diet 

Reducing the daily ration of the typical daily diet will lead to deficiency of essential nutrients such as proteins, vitamins and minerals. This will result in negative consequences: muscle atrophy, poor quality skin and coat, weakening of immune defenses etc.

Furthermore, the choice of a specific food makes it possible to provide adequate meal volume and prevent the cat from developing undesirable behavior, such as agitation, incessant meowing or stealing food.

DO NOT feed the cat leftovers

WEIGH the daily ration precisely 

Regularly weighing the daily ration is recommended, always with the same scales. Relying on volume measurements (i.e., cups) can result in accuracies and predispose to overfeeding.

DIVIDE the daily ration 

Dividing the daily ration into several servings provided multiple time during the day increases the post-prandial thermogenesis and so increases energy expenditure. Furthermore, it also reduces the feeling of hunger provoked by once daily feeding.

Exercise

Everything that can stimulate the cat to move is potentially beneficial:

• Look for games that the cat enjoys
• Put the food bowl somewhere else or place the kibbles throughout the home to encourage the cat to move around

Monitoring

Poor follow-up is a major cause of failure. Regular clinical observation makes it very easy to adjust the daily intake to the physiology of the individual cat.

The ideal is to have the owner visit every two weeks to weigh the animal and check that weight loss is advancing at 1 - 2% per week. If the pace is too slow (< 1%) the results will not be seen and if it is too fast (> 3% per week) there will be a greater risk of relapse and more extensive muscle atrophy at the end of the diet.

It is highly unlikely that the cat will lose weight at the same pace throughout the duration of the diet. Visits every other week will provide an opportunity to adjust the diet and modify the ration based on how weight loss is progressing.

A summary of the results at the end of the consultation provides a convenient way to view how the situation is progressing and how much still has to be done. It is also important to encourage the owner to continue with the dietary therapy.

Practical Pointers for Implementing and Monitoring a Weight Loss Diet

Weight Loss Phase

1. Determine the Target Weight

The target weight is based on the body condition score (BCS) at the first visit.

The BCS enables the estimation of excess weight as a percentage of body weight (see table).

For example a cat weighing 7.2 kg has a BCS of 5/5. Its excess weight is therefore 40% of its actual weight. The target weight is accordingly 7.2/1.4 = 5.14 kg

.

2. Calculate the Caloric Intake Needed to Produce Weight Loss

Based on the BCS and the ideal body weight, a number of kilocalories per kg of target weight is determined as follows.

This degree of caloric restriction is required to obtain a weight loss of 1 - 3% per week. For example, the energy needs of a cat with a target weight of 5.14 kg and a BCS 5/5 is 35 x 5.14 = 180 kcal/day.

3. Convert the Calorie Intake into a Daily Ration

The daily ration in grams corresponds to the calorie intake as calculated divided by the energy density of the food.

E.g., if the energy density of the diet is 3,500 kcal/kg, the daily ration is 180 kcal/3 500 = 0.051 kg or 51 g/day.

A mixture of dry and wet food is possible, provided precise quantities of each food are prescribed.

4. Adjust the Ration During Subsequent Visits

The ideal rate of weight loss is 1 - 2% per week. A diet is generally maintained for several months. Regular visits will provide opportunities to assess the suitability of the energy intake and adjust the pace of weight loss where necessary (if weight loss per week is > 3% or < 1%).

Figure 26. Diet transition plan.

Figure 27. Body weight curve.

Post-weight Loss Phase

Once the target weight is achieved, the cat enters the critical weight stabilization phase. Reverting to the cat’s original diet without controlling its intake will lead to rapid weight gain (rebound effect), while the final objective of a weight loss diet must be to stabilize the cat’s weight longterm.

Changing or Keeping the Food During the Weight Loss Phase

Keeping the same food makes it easy to see the gradual increase in the ration.

Gradually Increasing the Daily Energy Intake

Daily caloric intake must be gradually increased to reach the level at which the optimal weight will be maintained. This is increased by 10% every two weeks.

The cat must be weighed regularly during this phase to verify that the new caloric intake is not causing the cat to gain weight.

Establishing the Ultimate Ration

Caloric intake should ideally correspond to the cat’s maintenance energy requirement (MER), which is easy to find:

MER (kcal/day) = 55 x body weight (kg)

Most cats that are predisposed to obesity stabilize their weight at a level below the theoretical MER. Rather than reverting to the original food, the best option is to select a food that accounts for the animal’s risk factors for obesity (e.g., especially, neutering).

Key Points to Remember: Formulating a Food that Facilitates Weight Loss in Cats

Complete intake of all indispensable nutrients must be achieved when energy consumption is reduced.

A nutritional food formulated to produce weight loss must obviously be low in energy, but there are other imperatives that need to be addressed.

Nutritional Balance Adapted to Reduced Energy Consumption

The concept of balance is key. All intake of indispensable nutrients must be envisaged with respect to low consumption. The concentrations of trace elements, vitamins, indispensable amino acids and essential fatty acids must be higher than those in a maintenance food.

When reduced fat intake is necessary, foods with the lowest fat content are not always most effective. More than the fat content, it is vital that the calorie intake is reduced. If the effect of reducing the fat content is also to reduce the energy density of the food, other means are possible to achieve this. These include increasing the fiber and/or the water content, and adapting the physical structure of the food to reduce its density.

Increasing the Protein: Calorie Ratio Compared with a Maintenance Food

During the restriction phase, any deficiency in essential amino acids must be avoided, while any loss of lean mass must be minimized. The protein level must therefore take account of the animal’s lower food intake during the weight loss phase.

Conversely, too high a protein level is not advisable, as high-protein foods can easily induce overconsumption when rationing is not strictly observed (see the sidebar).

L-carnitine Supplementation

L-carnitine improves nitrogen retention and modifies the body mass in favor of lean mass. In obese animals, limiting the risk of the rebound effect is recommended after the weight loss diet.

Consideration for Skin and Joint Diseases Associated with Obesity

A weight loss diet generally extends over many months, during which time it is important to consider the cat’s general health. Diabetes, joint impairment and poor coat maintenance are the principal risks associated with obesity, so the nutritional approach must take them into account.

The available responses include:

• Reducing assimilable carbohydrate content and selecting a starch source with a low glycemic index (to reduce the development of insulin resistance)
• Incorporating substances like glycosaminoglycans (chondroitin sulfate and glucosamine) to fight premature wear on joint cartilage in overweight animals
• Strengthening nutritional intakes of key nutrients vital for optimal skin and hair coat (essential fatty acids, copper, zinc, vitamin A, etc.)

Dietary Strategies to Promote the Sense of Satiety in Cats

Obesity Introduction

Many low-calorie cat foods designed for weight loss diets are available in the veterinary market.

Unfortunately, these products are not always as successful as the manufacturers hope. The main problem is that the restricted intake changes the cat’s behavior. Begging, constant meowing and even aggression may prompt owners to increase the ration, which compromises the success of the diet. The solution is to use a nutritional food that quickly provokes a feeling of satiety in the cat, thus reducing the chances that it will demand more food while keeping to the recommended ration. The aim of this study was to test different dietary strategies for promoting the sense of satiety in cats (reducing food volume and/or energy intake).

Materials and Methods

The study was conducted on 16 adult cats of normal weight living in a cattery. These cats had always been fed with dry food. Four different dry foods were assessed in turn:

• A control food (protein: 41%; fat: 10%; TDF: 16%; metabolizable energy (ME): 3200 kcal/kg)
• A similar food but containing fiber with high water binding capacity (HWBC) (ME: 3115 kcal/kg)
• A high-protein food (HP) (protein: 46%; fat: 10%; TDF: 10%; ME: 3365 kcal/kg)
• A moderately high protein food (MHP) (protein: 36%, fat: 10%; TDF: 21%; ME: 3090 kcal/kg).

Four groups of 4 cats consumed these foods for 4 weeks, based on a Latin square protocol. After a 2-day transition, consumption was monitored for 5 days. The cats were fed ad libitum between 2 pm and 8 am next day (18 hours’ food availability) with continuous access to water. Each cat was allocated its own bowl, access to which was controlled by means of an electronic collar. The criteria for assessing satiety were: total consumption (ingested energy: kcal/kg weight/day), satiety during feeding (size of meal: g/meal) and inter-meal satiety (time interval between two meals after consumption of at least 1 kcal during the preceding meal (min : sec/1 kcal). The data were expressed as mean ± standard deviation.

Results

The cats consumed all the food. The results are shown in the table below.

Conclusion

Very little information is available on cats (based on rigorously controlled studies). This study was able to demonstrate a "satiety effect" of different nutritional formulations based on the dietary behavior observed (energy consumed, meal size and interval between meals). Contrary to the findings in humans and dogs, high protein content is linked to increased consumption. Restricting protein content (by substituting protein for fiber) is therefore an original strategy for limiting spontaneous food ingestion. The nature of the fiber is important. Insoluble fiber with high water binding capacity has a satiety effect on the stomach.

These observations have been confirmed by recent clinical studies. In the future, they should serve as a basis in the formulation of foods for treating obesity in cats.