In this article

1. Sugar & sweeteners
2. Starch & blood sugar
3. Protein
4. Fats
5. Vitamins & minerals
6. Fiber & gut health
7. Labels & energy
8. Cooking & storage

Sugar & sweeteners

Free sugars

All sugars added to food, plus the sugars naturally found in honey, syrups and fruit juice. WHO advises keeping them under 10% of daily energy, and ideally under 5%, which is about 6 teaspoons. Read more

Added sugars

Sugar that a cook or a manufacturer puts in, like the spoonful in a braising pot or the syrup in a glass of tea. The sugar already inside a banana or a glass of plain milk does not count. Read more

Glucose

The simple sugar your cells use as their main fuel. The starch in a bowl of rice also becomes glucose after digestion and then enters the blood. Read more

Fructose

A simple sugar found in fruit and honey, and one half of table sugar. It tastes sweeter than glucose and is handled mostly by the liver. In whole fruit it comes with fiber; in juice it is easy to take in more than you think. Read more

Sucrose

The scientific name for white table sugar or cane sugar. Each molecule is one glucose holding hands with one fructose, and the gut splits them apart. Read more

Sugar substitute

Ingredients that taste sweet with almost no calories, or far fewer than sugar. Some come from plants, like monk fruit and stevia; others are made in a lab, like sucralose and aspartame. Read more

Monk fruit

The round brown dried fruit you may have seen in Chinese herb shops. Its sweetness comes from compounds called mogrosides, about 100 to 250 times sweeter than cane sugar, and the body barely absorbs them, so they carry almost no calories. Read more

Erythritol

A sugar alcohol in white crystals, about 60 to 70% as sweet as cane sugar, with a light cooling feel on the tongue. It often provides the bulk in sugar substitute blends. Read more

Allulose

A "rare sugar" found in small amounts in dried figs and raisins. It is about 70% as sweet as cane sugar, very low in calories, and browns in the oven much like regular sugar. Read more

Stevia

The leaf of a South American plant, containing steviol glycosides that are a few hundred times sweeter than sugar. You need such a tiny pinch that it is usually blended with other ingredients to make it easy to measure. Read more

Sugar alcohol (polyol)

Sweeteners whose structure sits between a sugar and an alcohol, yet they contain no ethanol and cannot make you tipsy. Familiar examples are erythritol, xylitol in chewing gum, sorbitol and maltitol. Read more

Starch & blood sugar

Carbohydrate

The group that includes sugars, starch and fiber, often shortened to "carbs". Sugars and starch give about 4 kcal per gram, the familiar energy from rice, noodles, sweet potatoes and fruit. Read more

Starch

A long chain of many glucose units joined together, the way plants store energy in a grain of rice or a tuber. During digestion the chain is cut back down into glucose. Read more

Amylose and amylopectin

The two forms of starch in rice: amylose is a straight chain, amylopectin is branched. High-amylose rice cooks up fluffy and separate; sticky rice is almost all amylopectin, which is why it clings to your fingers. Read more

Resistant starch

Starch that slips through the small intestine undigested and feeds gut bacteria in the large intestine, much like fiber. Rice that is cooked and then cooled has a little more resistant starch than freshly cooked rice. Read more

Whole grain

A grain that keeps all three parts: bran, germ and endosperm, like brown rice, oats and whole wheat. White rice has had the bran and germ polished off, so it loses some fiber and B vitamins. Read more

Blood glucose

The amount of glucose in your blood at a given moment. It rises and falls naturally through the day, going up after meals before the body brings it back to baseline. Read more

Insulin

A hormone released by the pancreas when blood glucose rises. Think of it as a doorman that lets glucose move from the blood into cells, to be used right away or stored. Read more

Glycemic index (GI)

A 0 to 100 scale showing how fast a carb food raises blood glucose compared with pure glucose. Low GI means a gentler rise, but GI only describes speed, not amount. Read more

Glycemic load (GL)

A number that combines speed (GI) with the amount of carbs in a real portion. That is why a slice of watermelon, high in GI but low in carbs, still has a low GL. Read more

Glucose spike

A fast, steep rise in blood glucose after eating, common when refined starch or sweets are eaten on their own. Pairing them with vegetables, protein and fat helps the rise stay gentle. Read more

Protein

Protein

The nutrient that builds muscle, skin, hair, enzymes and antibodies, giving about 4 kcal per gram. Familiar sources are meat, fish, eggs, milk, tofu and beans. Read more

Amino acid

The small building blocks that make up protein. There are about 20 of them, and arranged in different orders they form thousands of different proteins in the body. Read more

Essential amino acid

The 9 amino acids the body cannot make and must get from food. The rest can be assembled from other building materials. Read more

Complete protein

A protein source with all 9 essential amino acids in useful proportions, such as eggs, fish, meat, milk and soy. Many plant proteins are short on one or two, but mixing them over the day fills the gap, like sticky rice with mung beans. Read more

Leucine

An essential amino acid that acts like a switch telling muscle to start building new protein. It is plentiful in whey, meat, eggs and soy. Read more

Muscle protein synthesis

The process of using amino acids to build and repair muscle fibers. Training plus enough protein spread across meals keeps it running steadily. Read more

Whey protein

The protein in the watery liquid left over from cheesemaking. It digests quickly and is rich in leucine, which is why it is often made into protein powder. Read more

Protein requirement

How much protein your body needs each day, usually counted by body weight. Healthy adults need about 0.8 to 1g per kg, so a 60kg person needs roughly 50 to 60g; active people and older adults often need more. Read more

Satiety

The feeling of having had enough that lasts between meals. Of the three main nutrients, protein tends to keep you full the longest, so a meal with enough protein makes the 3pm snack raid less likely. Read more

Fats

Fat

A dense energy source at about 9 kcal per gram, twice as much as protein or carbs. Fat helps you absorb vitamins A, D, E and K and makes food taste richer. Read more

Saturated fat

Fatty acids with no double bonds that pack tightly, so they are usually solid at room temperature, like lard, butter and coconut oil. WHO advises keeping them under 10% of daily energy. Read more

Monounsaturated fat

Fatty acids with one double bond, liquid at room temperature. Found in olive oil, peanut oil, avocado and nuts. Read more

Polyunsaturated fat

Fatty acids with two or more double bonds, including omega-3 and omega-6. Found in soybean oil, sunflower oil, sesame, walnuts and oily fish. Read more

Trans fat

Fat formed mostly when vegetable oil is partially hydrogenated to make shortening or hard margarine. WHO recommends removing industrial trans fat from the food supply. Read more

Omega-3

A family of polyunsaturated fats the body needs but cannot make enough of. ALA comes from flaxseed, chia and walnuts; EPA and DHA come from oily fish like salmon, mackerel and sardines. Read more

Cholesterol

A waxy fat the body needs for cell membranes and hormones, most of it made by the liver. Only animal foods contain cholesterol, so a bottle of vegetable oil labeled "cholesterol free" is simply stating the obvious. Read more

Smoke point

The temperature at which oil starts giving off a steady bluish smoke, a sign it is breaking down. For high-heat frying, pick an oil whose smoke point is above your cooking temperature. Read more

Emulsion

A mix of two things that normally will not blend, like oil and water, held together by a go-between. Mayonnaise is an oil-in-water emulsion kept stable by the lecithin in egg yolk. Read more

Vitamins & minerals

Micronutrients

The umbrella term for vitamins and minerals, needed in milligrams or micrograms a day. Small amounts, but essential, and most of them are already in a varied home meal. Read more

Heme and non-heme iron

Heme iron, found in red meat, liver and fish, is absorbed well. Non-heme iron, found in vegetables and beans, is absorbed less, but eating it with vitamin C rich fruit like guava or orange helps you absorb more. Read more

Calcium

The main mineral in bones and teeth, also needed for muscle contraction and nerve signals. Beyond milk, calcium comes from small fish eaten with their bones, dried shrimp, tofu and sesame. Read more

Vitamin D

The vitamin your skin makes in sunlight, which helps the body absorb calcium. Very few foods contain it naturally, mainly oily fish and egg yolk. Read more

Vitamin B12

A vitamin needed for blood and nerves, made by bacteria rather than by plants or animals themselves. Meat, fish, eggs and dairy are the main sources, so vegans usually need fortified foods or a supplement. Read more

Folate

Vitamin B9, needed to make new cells. Its name comes from the Latin word for "leaf", since leafy greens are rich in it, and beans and lentils are generous sources too. Read more

Potassium

A mineral that keeps fluids in balance and helps muscles and nerves work. Bananas are famous for it, but sweet potatoes, leafy greens and beans are good sources as well. Read more

Sodium

A mineral found mostly in table salt, fish sauce, soy sauce and seasoning powder. WHO advises under 2g of sodium a day, which is less than 5g of salt, about one teaspoon. Read more

Beta-carotene

The orange pigment in sweet potatoes, carrots, pumpkin and gac fruit, which the body turns into vitamin A as needed. Cooking it with a little oil helps absorption. Read more

Antioxidant

Substances that slow down oxidation, such as vitamin C, vitamin E and many plant compounds. Squeezing lemon over apple slices to keep them from browning is a kitchen example. Read more

Polyphenol

A huge family of plant compounds that give color and a slightly astringent taste to tea, coffee, cocoa and fruit. Green, oolong and black tea all come from the same leaf and differ in how much their polyphenols are oxidized. Read more

Fiber & gut health

Dietary fiber

The part of plant carbs that human digestive enzymes cannot break down. It moves on to the large intestine, keeps you regular and feeds helpful bacteria; WHO advises adults to eat at least 25g a day. Read more

Soluble fiber

Fiber that absorbs water and forms a gel, like basil seeds swelling in a glass of water. Found in oats, beans, apples and oranges. Read more

Insoluble fiber

Fiber that keeps its shape in water and adds bulk and softness to stool. Found in rice bran, seed hulls, vegetable stalks and fruit skins. Read more

Beta-glucan

A soluble fiber in oats and barley, and the reason a pot of oat porridge turns thick and creamy. It slows how fast food leaves the stomach, so you stay full longer. Read more

Inulin

A soluble fiber found in chicory root, onion, garlic and slightly green bananas. It is barely sweet and is a favorite food of helpful bacteria in the large intestine. Read more

Prebiotic

Food for the helpful bacteria in your gut, usually certain fibers such as inulin. If bacteria are the seeds, prebiotics are the fertilizer. Read more

Probiotic

Live microorganisms that offer a health benefit when eaten in adequate amounts, such as certain strains in yogurt. Not every fermented food still has live bacteria, since cooking or pasteurizing kills them. Read more

Gut microbiota

The community of tens of trillions of bacteria and other microbes living in the large intestine. They eat what you cannot digest, mostly fiber, and turn it into many compounds the body can use. Read more

Fermentation

The process in which microbes turn the sugars in food into acids, gas or alcohol. Pickled mustard greens, kimchi, fermented soybean paste and yogurt are all products of fermentation. Read more

Ultra-processed food

Industrial foods made mostly from refined ingredients and additives, like instant noodles, packaged snacks, soft drinks and sausages. Different from simple processing such as cooking, freezing or fermenting. Read more

Labels & energy

Calorie (kcal)

The unit for energy in food. On labels, a "calorie" is really a kilocalorie (kcal), the heat needed to warm 1 liter of water by 1°C. Read more

Macronutrients

The three energy-giving nutrients the body needs in large amounts: protein, carbs and fat. Protein and carbs give about 4 kcal per gram, fat about 9 kcal. Read more

Basal metabolic rate (BMR)

The energy your body burns at complete rest, just to keep the heart beating, lungs breathing and body warm. For most people it is the largest share of daily energy use. Read more

Total daily energy expenditure (TDEE)

All the energy you use in a day, including BMR, movement and the energy spent digesting food. TDEE formulas only give an estimate, not an exact measurement. Read more

Serving size

The amount a manufacturer picks to calculate the numbers on a label, sometimes smaller than the whole pack. Check the serving size before reading anything below it. Read more

Per 100g

Numbers given for every 100g of product, whatever the pack size. This lets you compare two foods from different brands and pack sizes fairly. Read more

% Daily Value (%DV)

The percentage column showing how much of a day's need for a nutrient one serving covers, usually based on a 2,000 kcal diet. Quick rule: around 5% is low, 20% or more is high. Read more

Ingredient list

Ingredients listed by weight, from most to least. Whatever comes first is what the pack contains the most of. Read more

Net carbs

Total carbs minus fiber, sometimes minus sugar alcohols too, to estimate the carbs that get digested. It is a packaging term rather than a standard labeling definition in many countries. Read more

Cooking & storage

Sous vide

Cooking food sealed in a vacuum bag in a water bath held at one precise, low temperature for a long time. That is how a chicken breast cooks evenly edge to center and stays juicy. Read more

Pasteurization

Heating food hot enough and long enough to bring harmful bacteria down to a safe level. A lower temperature needs a longer hold, so safety depends on both heat and time. Read more

Temperature danger zone

The range from about 5 to 60°C, where bacteria multiply fastest. Cooked food should not sit in this zone for more than 2 hours, like a pot of soup left on the stove all evening. Read more

Bacillus cereus

A bacterium whose spores survive the heat of cooking rice, then wake up and make toxins when rice sits at room temperature too long. That is why leftover rice should be cooled quickly and refrigerated soon. Read more

Freezing

Bringing food down to about -18°C or colder so bacteria stop growing. Freezing does not kill bacteria, but it keeps most of a dish's nutrients. Read more

Thawing

Bringing frozen food back to a soft state before cooking or reheating. The three safe ways are overnight in the fridge, in a sealed bag under cold water, or in the microwave followed by cooking right away. Read more

Starch gelatinization

When cooked in water, starch granules soak up water, swell and soften. That is how hard raw rice becomes soft cooked rice, and why brown rice needs a longer soak, since its bran layer slows water down. Read more

Starch retrogradation

As rice cools, starch chains pack back together tightly, making it firmer and drier and forming some resistant starch. Reheating with a little steam softens it again. Read more

Maillard reaction

A reaction between amino acids and sugars under high heat, giving color and aroma to bread crust, grilled meat and roasted coffee. Allulose takes part in it, which is why baked goods still brown. Read more

Caramelization

Sugar turning brown and fragrant on its own when heated, like the caramel sauce used for Vietnamese braised pork. Each sweetener reacts to heat differently, so not every one can make caramel. Read more

Meal prep

Cooking and portioning meals for several days, often in one weekend session. Cooling quickly, storing in the right compartment and labeling dates keep those boxes safe through the week. Read more