As per the FDA, the term complete & balanced means that a recipe must contain every nutrient listed in the profile at the recommended level. AAFCO is generally the nutritional profile most companies use but there are others such as FEDIAF & NRC. Complete & Balanced is a term that is in reference to commercial feed products that a dog eats day in and day out i.e. a dry food otherwise known as kibble. The nutrients that are stated by the likes of AAFCO are minimums meaning the minimums needed to keep a dog alive - hardly something to aspire to.
Complete and Balanced is a bit of a fallacy because every individual whether they be human or dog is an individual biochemically - what this means is I may need more Zinc than my sister for my body to run at its best so one cannot say that a specific set of nutrients at a specific amount is complete and balanced for me. In addition, you and I could both have the same amount of Zinc but you absorb less than I do because of genetic or environmental factors, so whilst a complete & balanced diet on paper may look good, it doesn't guarantee the end result is complete & balanced for the individual if this is all they are eating.
Humans & their balanced diets Humans by large eat highly processed diets that are lacking, making them insufficient & deficient in a number of nutrients that can lead to disease over time - so yes, balance is important but thinking that a human or a dog needs a specific set amount of nutrients in their meal (complete & balanced) at each meal/batch is overreach, it's fear mongering if the individual is eating a varied fresh food diet. Harvard University recommend for humans:
Notice how they do not recommend a set amount of nutrients i.e. vitamin B, D, E like we're made to believe dogs must have in each meal? Food pyramids and plates change over time and of course are highly debatable, so I am just using this as an example.
The accepted definition of a balanced diet (see how I said 'balanced' and not 'complete & balanced) is: a diet consisting of a variety of different types of food and providing adequate amounts of the nutrients necessary for good health.
Healthy humans eat a variety of fresh foods on rotation to allow them to access a wide variety of nutrients, they will generally follow some form of guideline depending on their personal preferences i.e. keto or government guidelines as shown in the above graphic from Harvard.
Even in the healthiest of humans, their individual meals would be far from 'complete and balanced' because that is not their goal, that kind of micro-managing nutrition actually leads to eating disorders, it's something that is often seen in body builders, physique competitors and similar. Let me show you all the things lacking in a healthy human recipe as shown in red and that's just the minerals section:
Their next meal may have heaps of Zinc and Calcium. The goal of healthy humans is to have a balanced diet not a 'complete and balanced' diet. Balance comes from eating a variety of ingredients on rotation over time. Some people may also choose to add a multi-vitamin to their routine to cover any potential nutrient gaps whether they be real or perceived - this is a tricky topic as they are usually synthetic nutrients which the body doesn't know what to do with, so we would recommend a powder or similar made from real food ingredients. In dogs, that may look like our occasional booster range.
The conflict with dogs I believe comes from kibble manufactures making pet parents believe that they must feed their dog a complete and balanced diet otherwise they will harm their dog - this of course is bias advice with financial benefit to those giving the advice.
Kibble companies will then go on to tell you why their specific formula is best for your dog, perhaps they'll have you believe your small, large or certain breed of dog requires a specific diet.....dogs survived for around 14,000 years without kibble, they were healthy enough to reproduce and keep their species going without highly processed diets that are typically high in carbs and contain synthetic nutrients.
A fresh food diet for dogs is really no different to what healthy humans eat - you power the body on what it was made to run best on. In dogs, they have a meat bias so whilst people continue to argue whether they are carnivores or omnivores - they have a meat bias and this should form the majority of their diet.
Dogs have a shorter digestive system to humans, different pH to humans and all the right bacteria in their digestive systems to run effectively and at their best on a fresh food diet.
Balance comes from eating a variety of ingredients on rotation so this means even if you're feeding a commercial complete & balanced fresh food product, I believe you should be rotating through different flavours and brands to ensure your dog is constantly being exposed to different nutrient profiles - of course some dogs have allergies etc. which may cause restrictive diets.
The short of it: Complete & balanced is a set of guidelines for kibble companies to follow to ensure dogs who eat only this diet get a minimum amount of nutrition to keep them alive.
Lets get real: I'm certainly not suggesting that you should just chuck some fresh food at your dog and hope it balances over time, I'm trying to help you understand where the term 'complete and balanced' came from and how it's not terribly relative to you as a fresh food feeding parent. You do absolutely want to continue your learning about what balance looks like in dogs and we have some great resources for that to use as a guide: https://www.freshfoodtribe.com/tools
We do offer complete and balanced fresh food recipes for those that just can't move past their fear: Puppies