1 January 2011

Busting Food Myths with Nicole Senior

Myth: You have to avoid carbs after 5pm to lose weight.

Nicole Senior

Fact: The time of day you eat carbs makes no difference to your weight – it’s the total amount you eat over the day that counts.
Avoiding carbs after five is popular advice, often given by people in the fitness industry to assist their clients lose weight. There’s even a diet book of the same name. While proponents may mean well, such advice simply adds to the mythology around weight loss. Following this advice might even work in the short term, but this only compounds the misunderstanding about why.

Similar to the previous myth ‘eating at night makes you fat’ (GI News November 2007) , the timing of carb intake is physiologically irrelevant; it’s the amount and type you eat that matters. There’s not a single study on the National Library of Medicine (PubMed) database about carbohydrate timing and weight loss (however, there’s plenty on carb timing and athletic performance if you’re interested).

Like other diets that restrict a particular nutrient or food group, the advice to avoid carbs after 5pm is simply a kilojoule/calorie reduction strategy dressed up as something catchier. When you think of a typical evening meal of chicken, noodles and vegetables, it’s not hard to see how skipping noodles creates a kilojoule deficit. If you can do it, great – it is possible to eat enough grain foods (preferably wholegrain and low GI) at other times during the day.

However a common experience of evening carb avoiders is they are still hungry after dinner and that’s when TV snacking can wreak havoc. Biscuits, chocolate and sweets are common evening saboteurs and they all contain carbohydrates. (And a side note, many people don’t understand that sugar is a carbohydrate too, which results in starchy foods getting a bad rap and sugar sailing through unsullied). Unfortunately the biscuits and chocolate also contain hefty amounts of saturated fat and kilojoules as well. This carb-craving may be physiological or psychological but it doesn’t really matter – the kilojoule damage is done.

The ‘no carbs after 5pm’ rule – and its variants 4pm and 6pm – is part of a dieting mentality we know is inherently unsustainable, although to be fair it is a much more moderate ‘low-carb’ diet. By deliberately depriving ourselves of commonly eaten, enjoyable foods we repeatedly build up psychological pressure that eventually results in overeating blow-outs: the classic dieting merry-go-round.

A far more balanced approach to lose weight is to eat smaller portions of carb-rich core foods like bread, pasta, rice, noodles and the like, and choose lower GI versions combined with plenty of vegetables and satisfying amounts of lean meat, chicken, fish or vegetarian alternatives. In nutrition circles, this is what we call a ‘balanced meal’. Unfortunately for many, the ‘moderation’ message is boring and unappealing.

This situation is not helped by the diet industries who also know the moderation message doesn’t sell and come up with all manner of trumped-up benefits and half-baked theories as to why their diet will actually work when all they are doing is selling creative ways to eat fewer kilojoules.

To lose weight we must reconcile the facts we must eat less and exercise more, and all the while ensure we eat quality foods to meet our nutritional needs. Blacklisting particular nutrients like carbs or fats is not helpful to this end. Prioritising nutrient rich foods from all the food groups in suitable amounts according to our energy needs is the answer.

Nicole Senior MSc (Nut&Diet) BSc (Nut) is an Accredited Practising Dietitian and Nutritionist. You can find good advice and great recipes using nutrient rich foods in Nicole’s books Eat to Beat Cholesterol and Heart Food available HERE.


Olga K said...
This comment has been removed by the author.
Anonymous said...

Why are you ignoring the effect carbs have on our glycogen levels? After dinner, most people are unlikely to do much physical activity and this is the reason why carbs in the evening should be avoided-you're simply not going to use up all that glycogen, which will lead to increase in fat.

Anonymous said...

Yes, but the next morning if/when people get up and exercise before breakfast they can tap into their glycogen stores for energy.
Plus your body has to keep your blood sugar levels even all the time and to do that it converts stored glycogen back to glucose..

Thanks for the article, I agree wholeheartedly. It frustrates me when friends avoid eating rice/pasta etc with their dinner but have no worries about their post dinner munching on icecream, low fat gelato, no fat lollies etc - I think you're spot on with the statement that a lot of people dont think of sugar as a carbohydrate and also think that no fat and low fat = low kilojoule!
Education is the key :)

Anonymous said...

My personal experience supports the "avoid high calories after 5pm" myth. So I avoid carbs and fats after 5 or 6 pm (carbs means for me poly- and monosaccharides as well, so no ice creams etc.).
However, when I start to eat after 5 or 6 pm, I immediately start to gain weight. This is visible on my face in 2-3 days, and later on my trunk also. So whatever the mechanism is (e.g. decreased total energy intake/day) this myth works in practice.

Anonymous said...

My experience over many years also confirms this 'myth.' Whilst the literature shows nothing to the contrary, one cannot prove the null hypothesis. I suspect that tests using normal subjects versus people having a high first insulin response might show an effect for the latter (high INS-30) group. The definitive studies have yet to be done, in my opinion, and I do believe the late Monsieur Montignac was onto something with the conjecture of a time-of-day/carb interaction.

Anonymous said...

To continue, I hypothesise a Time of Day X GI/GL X INS-30 interaction in predicting weight gain from isocaloric meals with equal carb energy content.

Anonymous said...

Strange, I keep posting and my post disappears.

Anonymous said...

The question of circadian effects on weight gain cannot be considered settled science. The following reference is a good place to begin:
Obesity (2009) 17 11, 2100–2102. doi:10.1038/oby.2009.264
Circadian Timing of Food Intake Contributes to Weight Gain

Deanna M. Arble1, Joseph Bass1,2, Aaron D. Laposky1, Martha H. Vitaterna1 and Fred W. Turek

Anonymous said...

A well written article! I agree totally with most of the things said. Also, what about people working in shifts? If this myth is correct, then those poor guys will probably have to eat in their sleep during the day and starve while they are working during the night which is totally impractical!
Once again, good article!

Jon Tapesa said...

I don't think there has to be a specific time, such as 5pm, bur cutting down on carbs in general is known to help with losing weight. Sadly, carbs are quite hard to avoid.