Simple and Complex Carbohydrates: What the Labels Mean and Why Whole Grains Matter More

Simple carbohydrates are sugars built from one or two units, such as glucose, fructose, sucrose and lactose. Complex carbohydrates are long chains: starch and fibre. The two labels describe chemistry and say little about health, because polished rice and maida are almost pure complex carbohydrate. ICMR-NIN's 2020 report asks for at least 100 to 130 g of carbohydrate a day from the age of one, and its 2024 guidelines ask that at least half of your cereals be whole grains. This entry is part of the carbohydrates section of the handbook.

What are simple and complex carbohydrates?

They are the two boxes into which textbooks and diet charts sort every carbohydrate. ICMR-NIN's Dietary Guidelines for Indians, 2024, puts it this way: glucose and fructose are simple carbohydrates found in fruits, vegetables and honey; sucrose, which is table sugar, and lactose, the sugar of milk, are made of two such units; starches and fibre are the two forms of complex carbohydrate, found in cereals, millets, pulses, vegetables and tubers. Carbohydrate supplies 4 kcal per gram.

Scientific bodies sort by chain length instead. The joint FAO/WHO expert consultation on carbohydrates divided them into sugars of one or two units, oligosaccharides of three to nine, and polysaccharides of more than nine: starch and the non-starch polysaccharides of plant cell walls. The handbook has separate entries on starch in food and on dietary fibre.

Where does the two-box classification break down?

It breaks down at starch, which is complex by any definition and still behaves very differently from one food to the next. The FAO/WHO consultation traced the term complex carbohydrate to a United States report of 1977, where it was coined to separate sugars from other carbohydrates and to encourage whole grains, fruit and vegetables. The experts pointed out that some starch is absorbed rapidly and has a high glycaemic index while some resists digestion, and judged that the term has little merit.

Indian flours make the point. In the Indian Food Composition Tables 2017, maida has 70.03 g of starch and 1.79 g of free sugars per 100 g; whole-wheat atta has 56.82 g and 1.80 g. Both are complex carbohydrate with the same trace of sugar. What separates them is fibre: 11.36 g in atta against 2.76 g in maida. The label fails in the other direction too. Of the 18.94 g of available carbohydrate in a ripe robusta banana, 13.65 g is free sugars, yet it is a whole fruit that brings fibre with it.

The glycaemic index, a measure of how fast a food raises blood glucose, tells the same story. ICMR-NIN's 2024 guidelines carry indicative values, each the mean of ten participants: 78.23 for rice, 65.66 for wheat chapatti and 37.95 for Bengal gram. The two-box scheme files all three together. NNWA's article on the glycaemic index of Indian foods explains how to read such numbers.

Starch, sugars and fibre in Indian staples

Read across each row of the table: almost everything in a cereal, a millet or a pulse is starch, so the simple and complex labels cannot rank them. The fibre column can. NNWA's table of carbohydrate in Indian foods lists the whole database, and the pages for milled and brown rice and wheat flour give the full panels.

How much carbohydrate do you need in India?

ICMR-NIN's Nutrient Requirements for Indians, 2020, set a figure for carbohydrate for the first time: a minimum of 100 to 130 g a day for everyone aged one year and above, the level needed for the brain's use of glucose. As a share of energy, its acceptable range is 45 to 65 per cent for adults. The 2024 guidelines plan a balanced diet at 50 to 55 per cent of calories from carbohydrate, which on 2,000 kcal is about 250 to 275 g at 4 kcal per gram.

No Indian document sets separate targets for simple and complex carbohydrate. The quality rules are about foods: whole grains, a ceiling on sugar and, in the 2020 report, about 30 g of fibre per 2,000 kcal. WHO's 2023 guideline says that carbohydrate for everyone aged two and over should come primarily from whole grains, vegetables, fruits and pulses. To turn the percentages into grams for your own energy need, use the macro calculator.

Whole grains against refined grains

A whole grain keeps its bran and germ; a refined grain is the starchy middle with those layers milled away. ICMR-NIN's 2024 guidelines place whole wheat, whole millets, minimally polished or hand-pounded rice and fresh flours from the local mill in the least processed group, and note that highly polished rice, maida and polished millets lose some fibre. IFCT 2017 shows the size of the loss: fibre falls from 4.43 g to 2.81 g per 100 g when brown rice is milled, and atta's 11.36 g compares with 2.76 g in maida.

Grinding matters as well as polishing. A review in the BMJ in 2018 noted that most whole grain in processed foods has been milled into fine flour, which raises its glycaemic index, and that a food labelled whole grain may not carry the benefits of an intact or minimally processed kernel. ICMR-NIN makes a similar point about packaging, warning that the words made with whole grain can be misread.

What does ICMR-NIN advise on whole grains and millets?

It advises that at least half of the cereals you eat be whole grains, and that millets make up a good part of them. The 2024 text allows millets up to 30 to 40 per cent of the day's cereals by raw weight, while the notes under its menu tables ask for 20 to 30 per cent for adults and 20 per cent for children up to ten. On the food-group averages in the same document, 100 g of millets has 65 g of carbohydrate and 7 g of fibre, against 72 g and 6 g for cereals.

A 2021 meta-analysis led from ICRISAT in India collected 65 studies and put the mean glycaemic index of millets at 52.7, against 71.7 for milled rice and 74.2 for refined wheat. The guidelines also ask that cereals be eaten with pulses in a ratio of 3:1 or 5:1, and that fruit be eaten fresh and not as juice. A separate article covers millets in the Indian diet.

What does the evidence say about carbohydrate quality?

It favours fibre and whole grains as the markers that predict health, and gives the glycaemic index weaker support. A series of systematic reviews in the Lancet in 2019 drew on 185 prospective studies and 58 trials with 4,635 adults. People eating the most fibre had a 15 to 30 per cent lower risk of death, heart disease, stroke, type 2 diabetes and bowel cancer than those eating the least, with the largest benefit between 25 g and 29 g a day. The certainty was graded moderate for fibre, low to moderate for whole grains and low to very low for glycaemic index.

A BMJ meta-analysis of 45 cohort studies in 2016 found that each extra 90 g of whole grain a day went with a 19 per cent lower risk of coronary heart disease and a 17 per cent lower risk of death from any cause. It found little evidence of an association for refined grains, white rice or total grains. These are observational findings, and people who choose whole grains differ in other ways too.

Two studies speak to rice-eating India. In a small crossover trial in Chennai, 15 overweight adults ate brown rice or white rice meals for five days each, and the 24-hour glucose response was 19.8 per cent lower on brown rice. The PURE cohort followed 132,373 people in 21 countries for 9.5 years: those eating 450 g or more of cooked white rice a day had a 20 per cent higher risk of developing diabetes than those eating under 150 g, and in South Asia the figure was 61 per cent.

Too much refined carbohydrate: who is at risk in India?

People whose plates are mostly polished rice or maida, with little pulse or vegetable, carry the most risk. ICMR-NIN's 2024 guidelines report that cereals supply 50 to 70 per cent of total energy in Indian diets against the 45 per cent they recommend, and that refined cereal intake is higher than it should be. They warn that sugar and refined cereals have a high glycaemic index and cause a sharp rise in insulin, and that depending on refined grains and sugar predisposes to obesity.

The same document, citing NFHS-5, puts type 2 diabetes at 15.6 per cent of men and 13.5 per cent of women aged 18 to 69, and abdominal obesity at 53 per cent of urban and 19 per cent of rural adults. Diet is one cause among several. At the other end, ICMR-NIN's minimum guards against too little; the entry on the low-carbohydrate diet looks at who such plans do not suit.

A worked example: two days on the same 250 g of cereal

This is an illustration, not a real person. Take a 31-year-old bank clerk in Chennai eating about 2,000 kcal, with the 250 g of raw cereal that ICMR-NIN's plate allows. On her usual day it is 60 g of maida as white bread at breakfast, 100 g of milled rice at lunch and 90 g at dinner. Using IFCT 2017, that cereal supplies 188 g of available carbohydrate, of which only 2.4 g is free sugars, and 7.0 g of fibre. By the old rule this is a day of complex carbohydrate.

Now follow the guideline. Breakfast becomes 60 g of ragi as dosa or porridge, lunch stays at 100 g of rice, and dinner becomes rotis from 90 g of atta. Whole grains are now 150 g of the 250 g, and millets 24 per cent. Available carbohydrate falls to 167 g, free sugars are 2.5 g, and fibre rises to 19.7 g. The simple and complex labels cannot tell these two days apart. Fibre can.

Common mistakes and myths about simple and complex carbohydrates

Two smaller mistakes follow from the same habit of trusting a label. Jaggery and honey are sugars like any other: IFCT 2017 finds 84.32 g of free sugars in 100 g of cane jaggery, a point taken up in NNWA's article on jaggery, honey and sugar. And a packet that says made with whole grain is not thereby minimally processed, as ICMR-NIN warns, so read the ingredients.

When should you see a doctor about carbohydrate?

See a doctor before making a large change to your carbohydrate intake if you have a medical condition that food affects directly. Moving from refined to whole grains suits healthy adults, and is best done over a few weeks. Changing the amount of carbohydrate is a different matter when medicines are involved, and no change of grain replaces a prescribed treatment.

Learning this subject at NNWA

Carbohydrate quality, food tables and meal planning are taught at NNWA, a private skill academy in Kolkata that teaches online in English and Hindi. Its courses, including the Diabetes Nutrition course, train people to coach healthy clients and to refer medical cases to a doctor. None is a degree or a dietitian qualification.