High-protein, high-meat diets have taken over the pet food aisle in recent years. Dietary protein is important for many reasons. It provides essential and nonessential amino acids for synthesis of proteins in the body that are necessary for tissue repair and maintenance, antibody and enzyme production, and as a source of energy.
In the world of nutrition, many nutrients and ingredients get placed on the "bad list" for a variety of reasons, but protein seems to be one of the lucky few that continues to increase in popularity. However, protein is one of the more financially, metabolically and environmentally expensive nutrients — particularly when the protein is from animal-based sources.
The financial cost of protein
Conserving the environment is typically what we think of in regard to sustainability, but economic viability is also a key component.
The cost of high-protein ingredients is on the rise globally. The economic environment is changing, with greater demand for animal protein sources in emerging nations with growing middle-class populations, such as China.
Zoonotic disease outbreaks, such as avian influenza, have caused intermittent decreases in supply as well as import and export restrictions between countries. The human, livestock, aquaculture and pet markets are all competing for high-quality protein ingredients.
At the same time, technological improvements in processing are resulting in more raw materials entering the human food chain and less being available for other sectors. Climate change is also creating challenges with crop production, creating a ripple effect in pricing throughout the supply chain.
Protein ingredients are typically the most expensive ingredients included in pet foods. Both the type and amount of protein affects the cost of the diet. Animal and plant ingredients are sources of protein, with each having advantages and disadvantages.
From a cost perspective, plant proteins tend to be less expensive. Rendered animal meals or dehydrated meats as well as plant proteins have a long shelf life, so food wastage is less of an issue compared to fresh meats, which have a short shelf life and require refrigeration or freezing.
Novel proteins are currently on trend, but can create supply chain challenges and the associated high price tag. The benefits of exotic proteins are primarily seen in pets with adverse food reactions who need a diet with a protein source to which they have not previously been exposed. Feeding exotic protein diets to the majority of pets is not sustainable.
Protein is metabolically expensive
Not only is protein economically expensive, but it is biologically inefficient as well.
Energy is essential to life. Dogs and cats can use three sources of energy: protein (amino acids), carbohydrates (glucose) and fat. When compared to carbohydrates and fats, the use of amino acids as an energy source is expensive. This is due to the structure of amino acids.
All amino acids contain an amino group and an acid group. When an amino acid is utilized for energy, the amino group (which contains nitrogen) is removed from the amino acid structure. The remaining structure can then be used to generate energy. If the detached amino group is not needed by the body for another purpose, it is converted in the liver to an end product, called urea, that is excreted in urine.
Pet foods need to provide all the nutrients required by dogs and cats in adequate amounts. Significantly exceeding an animal's requirement for protein or any nutrient is wasteful. While preventing nutrient deficiencies is critical, so too is avoiding nutrient excesses.
Not only is it wasteful to provide nutrients in quantities that greatly exceed requirements, but excess nutrient intake could also be harmful. Nutrient levels in high-meat diets may result in nutrient imbalances and excess levels of some nutrients — particularly protein, fat, calcium, phosphorus and magnesium.
High concentrations of calcium and phosphorus could negatively impact bioavailability of trace minerals, including iron, manganese, copper and zinc. Excess calcium and energy intake is associated with defects in bone growth in large breed dogs. Phosphorus restriction is recommended for dogs and cats with kidney disease.
While some dogs may require higher levels of certain nutrients, anything exceeding their requirements will be neither nutritionally nor environmentally beneficial.
Environmental impact of protein
Nutrient pollution is a widespread, costly and challenging environmental problem caused by excess nitrogen and phosphorus in the air and water.
Nitrogen, from urea and other sources, is an environmental contaminant. Overfeeding protein not only serves as an inefficient use of energy, but also leads to increased nitrogen (i.e. urea) excretion and environmental ammonia levels. The more protein that is fed above requirements, the more urea that gets excreted. High concentrations of urea in the urine result in yellow and burnt spots in grass.
Sustainability solutions
When it comes to feeding your pet, there are some simple steps that can be taken to decrease the ecological footprint and make sustainability a priority:
- Do not overfeed your pet. Learn how to identify if your pet is at an ideal body weight. Not only will you use less food, but you will also improve your pet's health by keeping him lean and fit.
- Choose a food with a moderate protein content.
- Consider choosing a diet that includes plant-based protein ingredients.
- Limit the use of exotic protein diets, except for pets suffering from adverse food reactions.
- Support companies that focus on sustainability in their business practices.
Sustainability is all about meeting the needs of today without compromising the needs of future generations. Keeping sustainability top of mind in our day-to-day choices has far reaching benefits for people, pets and the planet.
