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EVIDENCE LIBRARY

Nutrition & health
evidence reviews

Plain-language walk-throughs of the numbers behind everyday nutrition questions. Each review traces the commonly cited guidelines back to their sources. Educational only, never a substitute for your clinician.

OUR STANDARDPeer-reviewed sources · commonly cited guidelines · 41 reviews and counting
A close-up arrangement of fresh produce on a pale surface, with two red apples in front beside raspberries, a pear, oranges, avocados, carrots, broccoli, and leafy greensNewest review
Evidence review

Calories in an Apple: 95 in a Medium, by Size

This evidence review answers how many calories are in an apple: about 95 in a medium, 77 in a small and 116 in a large, plus carbs, sugar, and fiber by size.

27 min read
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All evidence reviews

Newest first. Every guideline figure links back to the review that explains it.

Stacked clear containers packed with portioned grains, vegetables and protein on a bright kitchen counter, ready for the weekEvidence review

Back-to-School Lunch Nutrition: Balanced Lunches Kids Eat

This evidence review covers back-to-school lunch nutrition: balanced lunch builds with illustrative calorie and...

28 min read
A colorful spread of fresh fruits and vegetables on a light table, including oranges, broccoli, carrots, raspberries, apples, and leafy greensEvidence review

How Much Vitamin C Per Day? RDA, Upper Limit, Food Sources

This evidence review answers how much vitamin C per day adults need: the NASEM RDA of 75 to 90 mg, the 2,000 mg upper...

36 min read
Bowls of plant proteins on a light surface: tofu, red and green lentils, chickpeas, black beans, peanut butter, seeds, and cashewsEvidence review

How to Get Protein Without Meat (Vegetarian and Vegan)

This evidence review shows how to get protein without meat: plant sources with commonly cited gram figures, honest...

32 min read
A colorful spread of fresh vegetables and fruit on a light table including carrots, sweet potato, leafy greens, apples, and berriesFood reference

Calories in a Potato: Baked, Boiled, Mashed, and Fries

This food reference breaks down the calories in a potato: near 160 in a medium baked potato and 90 per 100g, plus...

30 min read
An overhead contrast on a light table of whole-food carbs like brown rice, oats and whole grain bread on one side and refined carbs like white rice, white bread and a pastry on the otherEvidence review

Calories in Bread: Per Slice, White vs Whole Wheat

This evidence review breaks down the calories in bread: near 75 to 80 per slice of white, about 80 for whole wheat,...

29 min read
A glass of water beside a bowl of oatmeal topped with berries on a light table with a pitcher of water behindNutrition review

Calories in Oatmeal: Cooked Cup, Dry Half Cup, Packet

This nutrition review breaks down the calories in oatmeal: near 150 in a half cup of dry oats and 165 in a cooked cup,...

29 min read
An assortment of protein foods on a light table: grilled chicken, salmon, boiled eggs, lentils, tofu, yogurt, and edamameEvidence review

How Much Protein in Tuna? Canned, Fresh, and per Can

This evidence review breaks down how much protein is in tuna: near 20g per 100g of drained light tuna, about 22g in a...

30 min read
Two fresh skinless chicken breasts on a light wooden cutting board in a bright clean kitchenEvidence review

How Many Calories in Chicken Breast? (By Size)

This evidence review breaks down the calories in chicken breast by USDA portion, near 140 in 3 oz and 165 per 100g...

32 min read
An assortment of whole grains in bowls on a light surface, including brown rice, beside whole grain bread and a sweet potatoEvidence review

How Many Calories in Rice? (White vs Brown)

This evidence review breaks down the calories in rice by USDA portion, near 205 in a cooked cup and 130 per 100g, plus...

32 min read
A cooked salmon fillet beside grilled chicken, tofu, hard-boiled eggs, lentils, Greek yogurt and edamame in bowlsEvidence review

How Much Protein in Salmon? (By Portion)

This evidence review answers how much protein in salmon, with USDA-based figures per 3 oz, per 100g, and a fillet,...

30 min read
A whole banana beside a bowl of yogurt with berries, an apple, a bowl of oats, and a glass of water on a light surfaceEvidence review

How Many Calories Are in Bananas? 105 in a Medium

This evidence review answers how many calories are in bananas: about 105 in a medium, 72 in an extra small and 135 in...

33 min read
Fresh whole eggs on a light kitchen counter beside one cracked open to show a bright golden yolkEvidence review

How Many Calories in an Egg? 72 in a Large, by Size

This evidence review answers how many calories in an egg: about 72 in a large one, 54 in a small and 90 in a jumbo,...

36 min read
A colorful spread of fresh vegetables and fruit on a light table: broccoli, carrots, sweet potato, leafy greens, apples, a pear, oranges, avocado, and raspberries, the kind of high-fiber foods often discussed for regularityDigestive health

High-Fiber Diet for Constipation: What Helps

This article covers the high fiber foods constipation sufferers rely on, how fiber and water work together for...

28 min read
An overhead spread of water-rich whole foods on a light table: watermelon, cucumber slices, orange slices, a chilled soup, and a mug of teaFood reference

High-Fiber Foods: A Complete List by Group

This reference lists the foods with highest dietary fiber by group, legumes through seeds, with illustrative grams per...

33 min read
Whole-food protein sources in bowls: tofu, grilled chicken, salmon, eggs, lentils, yogurt, and edamame on a light surfaceNutrition review

Protein Shakes: When to Drink & How to Use

This evidence review explains protein shakes: when to drink one, how to use them, whey versus plant powders, timing...

28 min read
An overhead spread of water-rich whole foods on a light table: watermelon, cucumber slices, orange slices, a chilled soup, and a mug of teaEvidence review

Calories in Common Foods: A Quick Reference

This evidence review lists commonly cited calories in common foods, from a banana near 105 and an egg near 72 across...

33 min read
A spread of fresh fruits and vegetables on a light table, the kind of whole foods that make filling low-calorie snacksEvidence review

Low Calorie Snacks: 40+ Filling Ideas Under 200 Calories

Low calorie snacks that actually fill you up: this evidence review lists 40 plus ideas by category, with illustrative...

37 min read
A blank notepad and pencil beside a reusable shopping bag holding fresh vegetables, a chicken breast, a tray of eggs, and a bag of grains on a light kitchen counterEvidence review

How to Build a Healthy Grocery List (7 Steps)

This evidence review is a step-by-step walkthrough for how to make a healthy grocery list, from planning meals to...

27 min read
A glass of water being filled from a carafe on a bright kitchen counterEvidence review

How to Stay Hydrated (Daily Water Guide)

This evidence review covers how to stay hydrated day to day: a simple routine, the urine-color check, water-rich...

28 min read
A balanced plate of salmon, a whole grain, and vegetables beside a glass of water on a light kitchen tableReference

Daily Nutrient Intake Reference for Adults

A one-page reference for adult daily intake: protein, fiber, total water, sodium, and carbohydrate reference values...

4 min read
A reusable water bottle on a desk beside a keyboard and a plant, standing in for everyday water measurementReference

How Much Does a Gallon of Water Weigh? A Hydration and Measurement Guide

This reference explains how much a gallon of water weighs, how many ounces and water bottles are in a gallon, and how...

28 min read
An overhead view on a bright kitchen counter of several packaged foods turned to show their nutrition panels next to a small pile of white sugar cubes and a teaspoon, calm and clean in soft teal natural lightEvidence review

How to Spot Hidden Sugar on Food Labels

This evidence review shows how to find added sugar on labels step by step, reading the Added Sugars line, converting...

27 min read
An open blank notebook and pen beside a warm drink on a wooden table, ready for a day of loggingEvidence review

How to Count Your Macros (7 Steps)

This evidence review is a step-by-step walkthrough for how to count macros day to day, from setting targets to logging...

25 min read
An overhead view of a clean white plate arranged with protein-rich whole foods: grilled chicken breast slices, soft-boiled eggs, a scoop of green peas or lentils, a small bowl of plain yogurt, and cubes of tofu on a bright light tableEvidence review

How to Eat More Protein (8 Easy Ways)

This evidence review covers how to eat more protein: simple swaps for high protein breakfasts and snacks that lift a...

30 min read
An overhead view of one colorful balanced dinner plate: half filled with roasted and raw vegetables and a little fruit, a quarter with grilled chicken, and a quarter with a whole grain and cubed sweet potato, with olive oil and avocado to the sideEvidence review

How to Build a Balanced Meal (6-Step Plate Method)

This evidence review is a step-by-step walkthrough that shows how to build a balanced meal with the plate method, so...

27 min read
Several glass meal-prep containers on a clean kitchen counter, each filled with a balanced portion of grilled chicken, brown rice, broccoli, cherry tomatoes and leafy greens, in fresh natural daylightEvidence review

How to Meal Prep for the Week (7 Steps)

This evidence review is a step-by-step walkthrough that shows how to meal prep for the week, from planning a balanced...

27 min read
A person standing in a grocery store aisle holding a food package and reading the nutrition information printed on the back panel, calm and focused, in soft fresh natural lightEvidence review

How to Read a Nutrition Label (7 Steps)

This evidence review is a step-by-step walkthrough for reading a nutrition label, so you can quickly decode serving...

26 min read
An overhead spread of healthy whole-food carbohydrates on a light table: bowls of oats and other whole grains, whole grain bread, apples, bananas, berries, cucumber and carrot, and a bowl of chickpeasEvidence review

How Many Carbs Per Day? Recommended Daily Carb Intake

This evidence review answers how many carbs per day, with the recommended daily carb intake set in the NASEM DRI: 45...

36 min read
An overhead view of a single balanced dinner plate portioned into a palm of grilled chicken, a scoop of grain and cubed sweet potato, and a generous pile of colorful vegetables, with a halved avocado to the sideEvidence review

How to Calculate Your Macros (5-Step Method)

This evidence review is a step-by-step walkthrough that shows how to calculate your macros from your calories, so you...

26 min read
A balanced protein-rich meal of chicken, salmon, eggs, yogurt, lentils, and greens on a clean white plateNutrition review

How Much Protein Per Meal Can Your Body Use?

This evidence review explains how much protein per meal your body can use: you absorb nearly all of it, while...

26 min read
Raw ground beef mince beside browned cooked ground beef on a light wooden cutting board in a bright clean kitchenEvidence review

How Much Protein Is in Ground Beef?

This evidence review answers how much protein in ground beef, with figures per 100g, per ounce, by lean ratio, raw...

28 min read
Two fresh skinless chicken breasts on a light wooden cutting board in a bright clean kitchenEvidence review

How Much Protein Is in a Chicken Breast?

This evidence review answers how much protein in chicken breast, with commonly cited figures per 100g, per 4, 6, and 8...

26 min read
Fresh whole eggs on a light kitchen counter beside one cracked open to show a bright golden yolkEvidence review

How Much Protein in Eggs? Hard-Boiled, 2 Eggs, 3 Eggs

This evidence review answers how much protein in eggs: about 6 grams per large egg, with figures for a hard-boiled...

30 min read
An overhead contrast on a light table: a stack of white sugar cubes and a tall glass of dark cola soda on one side, a cluster of fresh whole fruit on the otherEvidence review

How Much Sugar Per Day Is Actually OK?

This evidence review lays out the commonly cited daily added-sugar guidance, near 25 grams for women and 36 for men,...

30 min read
An overhead spread of high-fiber whole foods on a light table: bowls of beans, lentils and chickpeas, a bowl of grains, blueberries, an apple and a pear, broccoli, carrots and leafy greensEvidence review

How Much Fiber Do You Need Per Day?

This evidence review lays out the commonly cited daily fiber guidance, near 25 grams for women and 38 for men, why...

27 min read
An overhead spread of protein-rich whole foods on a light table: eggs, chicken, salmon, yogurt, beans, lentils, tofu, and nutsEvidence review

How Much Protein Is in Common Foods? Eggs, Chicken, and More

This evidence review lays out commonly cited protein figures for everyday foods, from 2 eggs and 100g of chicken to...

27 min read
A balanced plate of whole foods with a glass of water on a light wood tableEvidence review

How Many Calories Do You Actually Need Per Day? The Evidence

This evidence review explains what a daily calorie need is, how resting metabolism and activity combine into a total,...

26 min read
A balanced meal of salmon, eggs, lentils, and leafy greens on a light tableNutrition review

How Much Protein Do You Actually Need? A Plain-Language Guide to the Numbers

The commonly cited baseline is about 0.8 grams of protein per kilogram of body weight per day, with higher intakes...

25 min read
A calm bedroom at dawn with soft morning light and teal accent pillows on a neatly made bedEvidence review

How Much Sleep Do You Actually Need? What the Evidence Says About the 8-Hour Rule

This evidence review traces where the 7 to 9 hour sleep rule comes from, how needs shift with age, what weekend...

28 min read
A glass of water being filled from a carafe on a bright kitchen counterEvidence review

How Much Water Do You Actually Need? The Evidence Behind the 8-Glasses Myth

The famous 8 glasses a day is not where hydration science actually landed. This evidence review covers what reference...

25 min read