Nutrition glossary
Diet and nutrition glossary
Diet advice is full of terms that get thrown around without much explanation. Here you'll find what they actually mean, with real foods, label examples and the catches that often get left out.
Each entry starts with a short definition you can read in a few seconds, then goes into the detail: how to work out your net carbs from a label, what a sensible calorie deficit looks like, or why the fruity breath and headaches of early keto happen. Pick a term below, or start with the group that matches what you're reading about.
Energy, weight and food quality
Calorie deficit
Eating fewer calories than your body burns, so it draws on stored fat.
Read definition →Macronutrient
Carbohydrate, protein or fat: the nutrients you eat by the gram that supply your calories.
Read definition →Diet quality
How healthy your overall eating pattern is, beyond just the calorie count.
Read definition →Added sugar
Sugar and syrups put into food or drink, as opposed to the sugar in whole fruit or milk.
Read definition →Carbs, blood sugar and keto
Net carbs
Total carbs minus fibre (and some sugar alcohols): the carbs your body actually digests.
Read definition →Glycemic index
A 0 to 100 scale of how fast a carb food raises your blood sugar.
Read definition →Ketosis
When low carb intake makes your body burn fat and produce ketones for fuel.
Read definition →Electrolytes
Minerals like sodium and potassium that control fluid balance, nerves and muscles.
Read definition →Eating patterns
Time-restricted eating
Eating all your meals within the same set window of hours each day, such as 16:8.
Read definition →Elimination diet
Cutting out suspected trigger foods for a few weeks, then adding them back one at a time.
Read definition →Where to go next
Once the words make sense, the diets start to as well. Read healthy eating basics for the foundations, compare plans side by side on the comparison page, or work through how to choose a diet. If you have a quick question, the diet FAQ may already answer it.