Q. Special K: is it the best cereal for weight loss?

Written by Catherine Saxelby on Monday, 28 February 2011.
Tagged: healthy eating, overweight, weight loss

Q. Special K: is it the best cereal for weight loss?
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A. Not really. We’ve all seen the advertisements and may even have bought it out of curiosity. But does it really work? What is it about Special K that helps you lose weight? Less kilojoules? Less fat? A ‘special’ ingredient? Let’s go through it in detail.


The ingredient list is nothing unexpected. Same as any flaked cereal with 5 added vitamins (B6 is unusual) and 3 added minerals (calcium and zinc are unusual).

Cereals (62%) (rice, wheat), wheat gluten, sugar, wheat flour, minerals (calcium carbonate, iron, zinc oxide), salt, barley malt extract, vitamins (niacin, vitamin B6, riboflavin, thiamin, folate).


Here’s our comparison of Special K with four other  similar flaked cereals, using the same serve size of 30 g, which is about one cup or an average bowl.


(without milk)













Special K

470 5.9 21.2 4.4 0.8 53


470 2.3 24.9 2.4 1.0 77


433 3.0 18.9 3.5 6.3 42

Just Right

447 2.7 21.5 8.6 2.4 60

Sultana Bran

427 2.9 18.9 6.8 4.5 73


Special K is marketed as a ‘dieter’s cereal’, but for the same serve size, Guardian, Just Right and Sultana Bran are lower in kilojoules. Surprised? So am I.


Of these five cereals, Special K is the highest in protein due to the added wheat gluten. Special K, with 1/2 cup of skim milk, provides more protein than a smoothie or even a poached egg on wholegrain toast. So it’s protein content is hard to beat. Another surprise! Protein has the advantage of extending satiety (satisfaction) after a meal, so this confirms one of its weight loss claims.

Sugar, fibre and GI

Apart from kilojoules, other important considerations for weight loss are sugar, fibre and GI which have all been shown to influence blood sugar levels which can in turn affect fullness and cravings. 


Cereals with more than 15 g per 100 g (5 g per 30 g serve) are considered high in sugar. In some cereals, such as Just Right and Sultana Bran, some or most of this sugar comes from fruit, but in the case of Special K, this is all added sugar. With exactly 15 g sugar per 100 g, Special K therefore is borderline moderate/high in sugar. Of the flake cereals, with no fruit, Special K has the highest sugar content. Since we are trying to keep sugar moderate, this is the least desirable one for nutrition reasons.


Health authorities recommend that we consume some 30 g a day. Children have lower fibre requirements. Apart from helping with bowel health, fibre helps with feelings of fullness and is essential in weight loss.

Guardian (6.3 g) and Sultana Bran (4.5 g) are the highest in fibre. Just Right (2.4 g) has a moderate amount of fibre and Cornflakes with 3.3 g is low. Special K (with only 0.8 g) provides the least which is only 3% of the recommended daily intake – the least likely to provide feelings of fullness and help stop snacking in the morning.


Special K has a low GI of 53 - just below the cut-off figure of 55, which is better than Cornflakes, Sultana Bran and Just Right. But, Guardian has an even lower GI value, which makes it preferable to Special K.

Serve size

A serve size of 30 g of Special K is quite small (a school aged child could eat this amount and possibly more!). This amount is unlikely to keep you feeling full from morning till lunch.

The high sugar content and low fibre (both poor at providing feelings of fullness) coupled to a very small recommended serving size all combine to make dieting efforts fail. 


One clear advantage of Special K is its high calcium. It contains 200 mg of calcium per serve - and that’s not including the calcium from the milk. A serve of Special K with ½ cup skim milk provides 359 mg of calcium – this is 50% of daily requirements for a 4-8 year old, 30% for a 12-18 year old and 35% for an adult. Pretty impressive.

Therefore, it would make a nutritious afternoon snack for adults (as well as kids) and be a healthier alternative to high sugar items such as doughnuts, muffins or ice pops. 


At 0.1 g per serve, Special K is low, at almost zero. But most cereals are low in fat, so whether a cereal has 0.1 g or 0.5 g fat is insignificant.

The bottom line

With its high sugar content, low fibre content and not the lowest GI, Special K does not have nutritional characteristics to help with weight loss. And it’s not even the lowest in kilojoules. Clearly, other cereals, such as Guardian, are preferable to Special K for their lower sugar content, much higher fibre content and lower GI value, and therefore in their ability to help with weight loss. All in all, Special K is...well, nothing special, as a weight loss breakfast cereal at least.  Do you agree?

Catherine Saxelby About the author

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Catherine Saxelby has the answers! She is an accredited nutritionist, blogger and award-winning author. Her award-winning book My Nutritionary will help you cut through the jargon. Do you know your MCTs from your LCTs? How about sterols from stanols? What’s the difference between glucose and dextrose? Or probiotics and prebiotics? What additive is number 330? How safe is acesulfame K? If you find yourself confused by food labels, grab your copy of Catherine Saxelby’s comprehensive guide My Nutritionary NOW!