I just started a new textbook called "The Essentials of Sport and Exercise Nutrition." This is a text written by the guys at Precision Nutrition. It's approximately a 450 page text, and it is definitely not a quick read, so I think as part of my studying I will make each chapter into a blog post (not a bad way to review the material, eh?). There are two "units" of the textbook. Unit 1 covers Nutritional Science (starting at the atomic level) and Unit 2 covers the Art of Nutrition Coaching.
I read two chapters yesterday and filled out the accompanying workbook (basically some review questions to make sure you understand the material in each chapter).
Chapter 0 - What is Good Nutrition?
The best way to achieve any goal is simply to identify the limiting factors (in other words, what is stopping you from reaching that goal?) and remove them. From a health perspective, there are essentially three types of limiting factors:
- Genetics
- Physical Activity
- Nutrition
Although genes play a role in every single function that occurs in the human body, it is unlikely that someone's genetics are their true limiting factor. Everyone has the ability to improve in some meaningful way, but perhaps not everyone can be an Olympic-level athlete. That leaves us with just physical activity and nutrition.
Exercise is a crucial component of health and longevity. Regular movement or activity of any kind is essential for maintaining movement quality throughout one's lifetime (think "use it or lose it").
Nutrition, however, is the most important aspect of one's health, and it is almost always the biggest limiting factor that prevents someone from reaching their health-related goals. So what is good nutrition?
Good nutrition must meet four criteria:
- it must property control energy balance
- it must provide nutrient density
- it must achieve health, performance, and body composition goals
- it must be honest and outcome-based
Now to cover each of those four in a little more detail...
Energy balance is simply the relationship between all sources of energy intake and energy output. Someone can be in a state of energy balance, positive energy balance, or negative energy balance. There are also many ways of achieving energy balance. One can increase energy outputs to match a high level of energy inputs. One could also decrease energy inputs to match a low level of energy outputs. Also, any combination of those could also work.
So should someone be in balance or in a positive or negative energy state? As with most questions, the answer is "it depends". There are positives and negatives to each scenario, and also whatever the "correct" answer for someone may be today will likely not be the case at some point in the future. Both positive and negative energy balance affect everything from metabolism to hormonal balance and mood.
A negative energy balance will lead to weight loss, but either a sustained or intense negative energy balance will also result in your body going into starvation mode. All non-survival functions will begin to slow down or shut down altogether (metabolic function, brain function, and reproductive function to name a few).
A positive energy balance will lead to weight gain (not necessarily bad if the weight is lean body mass), and it can also lead to poor health and cellular fitness. Plaques can build up in arteries, blood pressure and cholesterol can increase, and insulin resistance can result. Also, risk for certain cancers is correlated with weight gain (or being overweight).
Nutrient density is just the ratio of nutrients (vitamins, minerals, fiber, etc.) to calories in a food. A food with high nutrient density contains a large amount of key nutrients per 100 calories of food. Calorie density, on the other hand, is simply the ratio of calories to the actual weight of the food. Unless someone is purposely trying to gain weight (a young, undersized athlete or someone just wanting to pack on muscle for aesthetic purposes, etc.), the best combination of nutrient and calorie density for improving health would be a diet high in nutrient dense-foods and low in calorie-dense foods. The benefits of this combination or the following: easily controlled calorie intake (it is difficult to overeat broccoli!), longer periods of satiation, higher total essential nutrient intake, and more essential nutrients per volume of food.
Good nutrition is more than just weight loss or weight gain (which are just transient indicators of energy balance). Good nutrition must be a long-term set of habits that include goals related to health, performance, and body composition. To use an extreme example, someone who was solely interested in weight loss could get liposuction. In the short term, it would definitely result in a loss of body mass. However, it would do nothing for that person's health (think blood pressure, cholesterol, insulin sensitivity, etc.) or performance (performance doesn't have to be a sport, it could simply be moving around easily without pain).
Finally, good nutrition requires one to be honest with themselves and use outcome-based decision making. If someone says "I followed the plan exactly, but I still didn't lose the weight" then it is likely that one of two things is happening: they didn't really follow the plan, or the plan sucks. If someone consistently does the right things, results must follow. Cause and effect. So if the results aren't coming, it's time to evaluate both the plan and the compliance with said plan.
My next blog will cover Chapter 1 - Cell Structure and Function. I'll try to strictly limit it to how nutrition impacts cellular structure and function.
