5 Principles of Good Nutrition
Is wine bad for you?
Sure, some research cautions about an increased risk of cancer. It’s also clearly not something you want to drink before using a chainsaw or driving a van full of children. Then again, wine comes from grapes, which contain health-promoting phytochemicals, and some research points to a potential heart benefit.
What’s more, you might be a person who has the ability to enjoy it responsibly and in moderation.
So the answer is… it depends.
What's annoying is you could say the same about a range of foods, diets, and nutritional strategies. That’s because, when it comes to nutrition, there’s a lot we don’t know for sure. Which can make it pretty hard to give cut-and-dry answers on what to eat for better health.
But you're not reading this because you want to hear, it depends.
So what nutrition concepts can you really be confident about?
As it turns out, almost everyone agrees on five evidence-based principles. But before we get into what we know with almost 100 percent certainty, let’s explore why and how we know it.
How many studies does it take to confirm a nutritional claim?
We can’t answer that question with a specific number. Truth is, nothing in nutrition science is ever completely certain, but we can get pretty close.
Quantity
How much research is there? Only a few studies? Or hundreds? The more vast the body of research, the more confident you can feel about a specific finding or theory.
Quality
Look for research conducted by people at the top of their field and published in well respected, peer-reviewed journals.
Specifically, we want to see:
Randomized controlled trials that test a specific treatment on a group of participants. Another group of people (the placebo group) doesn’t get the treatment, but both groups think they’re getting it.
Systematic reviews that discuss the available studies on a specific question or topic. Typically, they use precise and strict criteria for what’s included.
Meta-analyses that use complex statistical methods to combine the findings of several studies. Pooling together the data from many studies increases the statistical power, offering a stronger conclusion than any single study.
Scope
We look for research that dates back decades rather than studies that just started appearing during the past few years.
Consistency
Our confidence goes up when many studies arrive at the same conclusion rather than opposite ones.
Universality
Studies have looked at how a nutritional concept affects different types of people, under different conditions, in different geographic locations.
5 principles of good nutrition
So which nutrition claims pass the five-factor test?
Principle #1: Weight loss and weight gain come down to one key equation.
Everyone knows this one, though not everyone believes it. It’s the energy balance equation, also known as calories in, calories out
[Energy in] – [Energy out] = Changes in body stores
In other words:
When you take in more energy (or calories) than you burn, you gain weight.
When you take in less energy than you burn, you lose weight.
When you take in the same energy as you burn, you maintain.
So you might be wondering: How do we know this with absolute certainty whereas “wine is bad/good for you” is still up for debate?
First, like gravity, this principle is easy to test. With gravity, you can continually release a heavy object. No matter how many times you try it, the object falls. It’s the same with energy balance. If you reduce “energy in” and increase “energy out,” you always get the same result: Bodyweight goes down.
Second, the energy balance equation comes from the first law of thermodynamics: Energy can neither be created or destroyed, only transferred from one state to another.
Humans can’t create energy from nothing. We convert it from food. And any excess energy we take in doesn’t magically vanish: Your body either increases “energy out” (often by turning up the metabolism) or stores the excess.
Scientific laws are as close to facts as we can get. Can they be updated over time? Sure. In this case, however, the law has stood firm for well over a century.
So, why do some people say “Not all calories are equal!”?
As you can see from the illustration below, many complex factors influence “calories in” and “calories out.” Your brain, especially, can turn up or turn down metabolism, exerting a massive influence on “calories out.”
But, lots of factors can affect different parts of the equation.
What does this mean for you?
If someone wants to gain or lose body mass, they’ll want to consider overall energy balance and how to shift it in their favor. Here are a few ways to do just that.
To increase calories out:
Add strength training to build more muscle, boost overall metabolism, and burn more calories.
Increase daily activity by taking the stairs, parking farther from your destination, and/or using an activity tracker to nudge you to take more steps.
Boost protein intake to increase the thermic effect of digestion.
Practice self care to reduce stress and improve sleep—both important for a healthy metabolism.
To reduce calories in:
Consume more fiber-rich vegetables to reduce the number of calories your body absorbs.
Consume more protein to reduce appetite and therefore overall energy intake.
Eat slowly so you can tune into hunger and fullness signals, and stop eating when you are satisfied, not stuffed.
Use hand portions to guide how much you eat.
Get enough sleep to reduce hunger and cravings for sweets.
Principle #2: Protein is the most important macronutrient to get right.
Why? Two reasons.
Reason #1: It helps you eat less, without feeling so hungry.
Research consistently shows that protein helps you feel full longer and, as a result, lose weight. That’s, in part, because it takes longer for the body to break down protein than carbs or fat.
Protein also stimulates the release of satiety hormones in the gut.(1,2)
So when you eat protein, you naturally tend to eat less, and it makes a big difference. Doubling your protein intake could help you to spontaneously consume 400 fewer calories a day. For reference, that’s roughly the number of calories in 1 ½ cups of ice cream.(3)
Reason #2: Protein makes it easier to build and maintain muscle.
Without adequate protein, our bodies just can’t function well. We need amino acids (protein’s building blocks) to produce important molecules like enzymes, hormones, neurotransmitters, and antibodies.
So when we don’t eat enough protein, our bodies plunder it from elsewhere, like our muscles, resulting in muscle loss. This is especially true if we’re eating fewer calories than we’re burning.
On the flip side, a high-protein diet seems to maximize muscle protein synthesis, which should lead to more muscle gain for people who are strength training and consuming enough calories.
This is probably one of the reasons high-protein diets are better for improving body composition than normal or low-protein diets.
A review of 38 studies found that, for people who are out of shape, consuming extra protein won’t magically build any muscle—no surprises there. But for people who are really pushing themselves in the gym, eating more protein seems to boost their results, helping them gain even more muscle.(4,5)
What does this mean for you?
The right amount of protein for each person varies on a number of factors such as age, gender, and goals.
Someone interested in packing on muscle for a bodybuilding competition might aim for as many as 50 grams of protein (or about two palm-size portions of meat) at every meal. Someone hoping to work off 20 extra pounds is going to need much less than that.
Principle #3: As food processing increases, nutrient density decreases.
Minimally-processed whole foods (such as grains, nuts, eggs, and fish) contain a vast selection of vitamins, minerals, phytonutrients (plant nutrients), and zoonutrients (animal nutrients).
Though we’re still unraveling exactly which nutrients do what, a wealth of research consistently points to one resounding conclusion:
Humans are healthier when they consume more whole foods and fewer refined ones.
This is probably because the greater the degree of processing, the higher the likelihood that a food:
Has lost nutritional value, such as fiber, essential fatty acids, vitamins, minerals, phytonutrients, and zoonutrients.
Has gained additives, preservatives, fillers, sugar, sodium, unhealthy fats, and/or refined starch.
So it makes sense that a diet rich in minimally-processed whole foods can lead to lower rates of heart disease, cancer, depression, and type 2 diabetes, among other health problems.(6-11)
Minimally-processed whole foods are also rich in fiber and/or protein—two nutrients that help bolster satiety, and they tend to have fewer calories per serving than highly-processed refined foods.
Both traits make it easier for us to control our weight.
One randomized controlled trial even found that people ate a stunning 500 more calories per day when they consumed a diet rich in ultraprocessed foods compared to a diet rich in minimally-processed whole foods.12 That’s essentially the equivalent of consuming an extra meal a day.
In fact, minimally-processed whole foods may be what all successful diets share in common.
Recent studies have shown that participants experienced the same amount of weight loss—regardless of carb or fat intake—as long as they minimized their consumption of refined sugars, flours, and other processed foods, while emphasizing whole foods like veggies. They also experienced similar improvements in blood pressure, insulin, glucose, and cholesterol levels.(13,14)
Progress is much more important than perfection.
So rather than separating foods into “whole” and “not whole” categories, imagine a spectrum. As you can see from the graphic below, as food becomes more processed and refined, it loses a little bit of its nutritional power.
Principle #4: Fruit and vegetables reduce disease risk—and may help you lose weight, too.
Among the various types of whole foods, produce deserves special mention.
Fruits and veggies are loaded with health-promoting antioxidants, vitamins, minerals, fiber, and phytonutrients.
A huge body of evidence from the past 20 years definitively shows that consuming more produce can help prevent a wide range of health problems, including diabetes, stroke, heart disease, high blood pressure, and cancer.
For example, by simply increasing vegetable and fruit intake, experts predict that we could prevent 20 percent or more of all cancer cases, and avoid approximately 200,000 cancer-related deaths annually.(15-19)
An increasing number of studies also suggest that consuming a diet rich in antioxidant and anti-inflammatory foods such as fruits and vegetables may lower the risk of developing neurodegenerative disease.(20-22)
And, when it comes to cognitive performance, food beats supplements. Once nutrients, such as antioxidants, are isolated from produce and inserted into capsules, they seem to lose some (perhaps all) of their power.
Finally, an eating pattern rich in produce can help you more easily control your weight. This effect is thanks to their fiber and water content, which helps fill you up on fewer calories. An entire head of cauliflower, for example, contains only about 150 calories.(23,24)
What does this mean for you?
No one fruit or veggie is king. Rather than sticking to one magic powerfood—for example, eating blueberries every single day—aim for a variety. Try to eat a wide rainbow of colors everyday.
Principle #5: Sleep affects what you eat—as well as your overall health.
People can nail everything with their nutrition but still struggle to reach their goals. Often, that’s because they’re not getting enough sleep, and they only make progress once they prioritize sleep.
What’s the connection?
If you sleep 5 or 6 hours when you really need 7 or 8, you keep your body in a chronically sleep-deprived state, impairing your body’s ability to regulate several key hormones.
Ghrelin levels rise, triggering hunger.
Leptin falls, so it takes longer to feel full.
Endocannabinoids increase, making your perception of foods seem more pleasurable.
End result: You can’t keep yourself away from the cookies.(25-27)
By not getting enough sleep, you’re just hungrier and you crave sweets more than you otherwise would. You’re also tired, so you exercise and move less, and more awake time means more time to raid the kitchen.
Bottom line: Sleep-deprived people tend to eat at least 300 more daily calories than people who get enough sleep.28
In addition to interfering with weight loss, lack of sleep also erodes health.
Just one night of sleep deprivation can lead to increased blood pressure the following day.(29-32) Each year, when nearly 1.5 billion people lose an hour of sleep due to daylight savings time, rates of heart attacks jump.(33,34)