The theory of somatotypes was developed in the 1940s (by a psychologist) and has been subsequently rejected and disproved as a viable means to predict or determine individual physiology or responses to training and diet. Yet, it still is prevalent in the fitness industry and occasionally pops up in articles or videos with recommendations based on a self-evaluation or quiz to determine “your body type”.
When we also factor in that as you train and make progress, your physique will change if things are being done correctly. So, taking “body type” recommendations and sticking to them long-term will become more of a hindrance to developing your potential physique.
There are plenty of people who start their journey looking like what we might consider an “ectomorph” or “endomorph” but after they spend time training and building muscle or losing fat, look more like a “mesomorph”. Did their genetics change? Of course not. But their nutritional and training requirements for continued progress certainly have.
Another consideration is that you cannot necessarily base nutritional recommendations, such as macronutrient percentages, on physical appearance. Sure, body fat levels will play a role and might influence them a bit, but the primary factors that will drive nutritional requirements are going to be the type of training (stimulus), training volume, training frequency, the individual’s current goal, and biological factors like digestive health and if there is currently inflammation present.
This approach really falls short the more we understand the impact of training stimuli on a biological level.
Some types of training require relatively greater amounts of carbohydrates and less fat, others will be better suited to higher fat and lower carbs, while some require higher protein intake than others. These differences are regardless of what your body “looks like”, but the magnitude to which they change will depend on how the individual responds or handles nutrients.
This is a cornerstone component of understanding and designing training programs and coaching individuals for the best results. It is also why we provide guidelines in the N1 Training Programs as to the suggested ranges for nutrition to make sure you’re at least headed in the right direction.