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.
This is a lot easier to see when you compare specific whole foods to their more highly-processed equivalents.
As you can see, the less-processed steak and potato dinner contains about 350 fewer calories and a fraction of the sodium as the fast food burger with fries, as well as a heck of a lot more protein, fiber, and other nutrients.
That’s just one comparison.
But you could analyze any whole food along with its more refined counterpart and see similar differences in calories, sodium, and nutrients.
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.
T
he goal with whole foods isn’t to get things “perfect.” Instead, focus on making them “just a little bit better.”
A rotisserie chicken from the supermarket may not be a pastured, lovingly hand-raised, heritage Chantecler roasted in a high-end convection oven… but it sure beats fried chicken wings.
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)
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Precision Nutrition
Ghazzawi HA, Mustafa S. Effect of high-protein breakfast meal on within-day appetite hormones: Peptide YY, glucagon like peptide-1 in adults. Clinical Nutrition Experimental. 2019 Dec 1;28:111–22.
Wang S, Wang C. The Effect of Dietary Protein on Weight Loss, Satiety, and Appetite Hormone. Available from: https://www.actascientific.com/ASNH/pdf/ASNH-03-0207.pdf
Weigle DS, Breen PA, Matthys CC, Callahan HS, Meeuws KE, Burden VR, et al. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutr. 2005 Jul;82(1):41–8.
Pasiakos SM, McLellan TM, Lieberman HR. The effects of protein supplements on muscle mass, strength, and aerobic and anaerobic power in healthy adults: a systematic review. Sports Med. 2015 Jan;45(1):111–31.
Schoenfeld BJ, Aragon AA. How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. J Int Soc Sports Nutr. 2018 Feb 27;15:10.
Farvid MS, Chen WY, Michels KB, Cho E, Willett WC, Eliassen AH. Fruit and vegetable consumption in adolescence and early adulthood and risk of breast cancer: population based cohort study. BMJ. 2016 May 11;353:i2343.
Srour B, Fezeu LK, Kesse-Guyot E, Allès B, Méjean C, Andrianasolo RM, et al. Ultra-processed food intake and risk of cardiovascular disease: prospective cohort study (NutriNet-Santé). BMJ. 2019 May 29;365:l1451.
Rico-Campà A, Martínez-González MA, Alvarez-Alvarez I, Mendonça R de D, de la Fuente-Arrillaga C, Gómez-Donoso C, et al. Association between consumption of ultra-processed foods and all cause mortality: SUN prospective cohort study. BMJ. 2019 May 29;365:l1949.
Adjibade M, Julia C, Allès B, Touvier M, Lemogne C, Srour B, et al. Prospective association between ultra-processed food consumption and incident depressive symptoms in the French NutriNet-Santé cohort. BMC Med. 2019 Apr 15;17(1):78. \
Martínez Steele E, Juul F, Neri D, Rauber F, Monteiro CA. Dietary share of ultra-processed foods and metabolic syndrome in the US adult population. Prev Med. 2019 Aug;125:40–8.
Fiolet T, Srour B, Sellem L, Kesse-Guyot E, Allès B, Méjean C, et al. Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort. BMJ. 2018 Feb 14;360:k322.
Hall KD, Ayuketah A, Brychta R, Cai H, Cassimatis T, Chen KY, et al. Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake. Cell Metab. 2019 Jul 2;30(1):67–77.e3.
Gardner CD, Trepanowski JF, Del Gobbo LC, Hauser ME, Rigdon J, Ioannidis JPA, et al. Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial. JAMA. 2018 Feb 20;319(7):667–79.
Shan Z, Guo Y, Hu FB, Liu L, Qi Q. Association of Low-Carbohydrate and Low-Fat Diets With Mortality Among US Adults. JAMA Intern Med [Internet]. 2020 Jan 21; Available from: http://dx.doi.org/10.1001/jamainternmed.2019.6980
Wang X, Ouyang Y, Liu J, Zhu M, Zhao G, Bao W, et al. Fruit and vegetable consumption and mortality from all causes, cardiovascular disease, and cancer: systematic review and dose-response meta-analysis of prospective cohort studies. BMJ. 2014 Jul 29;349:g4490.
Hung H-C, Joshipura KJ, Jiang R, Hu FB, Hunter D, Smith-Warner SA, et al. Fruit and vegetable intake and risk of major chronic disease. J Natl Cancer Inst. 2004 Nov 3;96(21):1577–84.
He FJ, Nowson CA, MacGregor GA. Fruit and vegetable consumption and stroke: meta-analysis of cohort studies. Lancet. 2006 Jan 28;367(9507):320–6.
Yokoyama Y, Nishimura K, Barnard ND, Takegami M, Watanabe M, Sekikawa A, et al. Vegetarian diets and blood pressure: a meta-analysis. JAMA Intern Med. 2014 Apr;174(4):577–87.
Farvid MS, Chen WY, Rosner BA, Tamimi RM, Willett WC, Eliassen AH. Fruit and vegetable consumption and breast cancer incidence: Repeated measures over 30 years of follow-up. Int J Cancer. 2019 Apr 1;144(7):1496–510.
Khaw KT, Bingham S, Welch A, Luben R, Wareham N, Oakes S, et al. Relation between plasma ascorbic acid and mortality in men and women in EPIC-Norfolk prospective study: a prospective population study. European Prospective Investigation into Cancer and Nutrition. Lancet. 2001 Mar 3;357(9257):657–63.
Fortune NC, Harville EW, Guralnik JM, Gustat J, Chen W, Qi L, et al. Dietary intake and cognitive function: evidence from the Bogalusa Heart Study. Am J Clin Nutr. 2019 Jun 1;109(6):1656–63.
Preventing dementia: do vitamin and mineral supplements have a role? [Internet]. [cited 2020 Feb 27]. Available from: https://www.cochrane.org/news/preventing-dementia-do-vitamin-and-mineral-supplements-have-role
Bertoia ML, Mukamal KJ, Cahill LE, Hou T, Ludwig DS, Mozaffarian D, et al. Changes in Intake of Fruits and Vegetables and Weight Change in United States Men and Women Followed for Up to 24 Years: Analysis from Three Prospective Cohort Studies. PLoS Med. 2015 Sep;12(9):e1001878.
Guyenet SJ. Impact of Whole, Fresh Fruit Consumption on Energy Intake and Adiposity: A Systematic Review. Front Nutr. 2019 May 8;6:66.
Hanlon EC, Tasali E, Leproult R, Stuhr KL, Doncheck E, de Wit H, et al. Sleep Restriction Enhances the Daily Rhythm of Circulating Levels of Endocannabinoid 2-Arachidonoylglycerol. Sleep. 2016 Mar 1;39(3):653–64.
Hogenkamp PS, Nilsson E, Nilsson VC, Chapman CD, Vogel H, Lundberg LS, et al. Acute sleep deprivation increases portion size and affects food choice in young men. Psychoneuroendocrinology. 2013 Sep;38(9):1668–74.
Schmid SM, Hallschmid M, Jauch-Chara K, Born J, Schultes B. A single night of sleep deprivation increases ghrelin levels and feelings of hunger in normal-weight healthy men. J Sleep Res. 2008 Sep;17(3):331–4.
Al Khatib HK, Harding SV, Darzi J, Pot GK. The effects of partial sleep deprivation on energy balance: a systematic review and meta-analysis. Eur J Clin Nutr. 2017 May;71(5):614–24.
Doyle CY, Ruiz JM, Taylor DJ, Smyth JW, Flores M, Dietch JR, et al. Associations Between Objective Sleep and Ambulatory Blood Pressure in a Community Sample. Psychosom Med. 2019;81(6):545–56.
Aggarwal B, Makarem N, Shah R, Emin M, Wei Y, St-Onge M-P, et al. Effects of Inadequate Sleep on Blood Pressure and Endothelial Inflammation in Women: Findings From the American Heart Association Go Red for Women Strategically Focused Research Network. J Am Heart Assoc [Internet]. 2018 Jun 9;7(12). Available from: http://dx.doi.org/10.1161/JAHA.118.008590
Calhoun DA, Harding SM. Sleep and hypertension. Chest. 2010 Aug;138(2):434–43.
Meininger JC, Gallagher MR, Eissa MA, Nguyen TQ, Chan W. Sleep duration and its association with ambulatory blood pressure in a school-based, diverse sample of adolescents. Am J Hypertens. 2014 Jul;27(7):948–55.
Janszky I, Ljung R. Shifts to and from daylight saving time and incidence of myocardial infarction. N Engl J Med. 2008 Oct 30;359(18):1966–8.
Sandhu A, Seth M, Gurm HS. Daylight savings time and myocardial infarction. Open Heart. 2014 Mar 28;1(1):e000019.
