Low Carb Dieters: Thinner but Grumpier?

By Mike Howard on Nov 24, 2009

Restricting carbs may negatively impact your mood according to a recent study published in the Archives of Internal Medicine. Here are the study details and how it applies to you.

Researchers randomized 118 obese people aged 24 to 64 to either a low fat or low carbohydrate restricted energy diet and followed participants for 12 months and measured both body weight and mood scores.
Mood scores for both groups improved dramatically in the first eight weeks, although the studies authors said this may be due to early weight loss.
Of the 55 people who completed the trial, researchers found participants in the low fat group maintained the improvement over the course of the trial, while mood scores in the low carbohydrate group returned towards more negative baseline levels.
Said the authors "This outcome suggests that some aspects of the low-carbohydrate diet may have had detrimental effects on mood that, over the term of one year, negated any positive effects of weight loss."
The reason why restricting carbs can impact mood is the effect on serotonin - a neurotransmitter that regulates among other things, mood.

A Few Thoughts

Carbohydrate restriction can and does work well for many people, although long term results tend to be poor.
For those whom low carbing works well, I'm thinking the results will negate any negative mood that may present itself.
The fact that only half the participants completed the study speaks to the difficulty in sticking with any restrictive diet - low carb or otherwise.
I'm always perplexed as to why researchers and the public at large can't get out of this "low carb" vs. "low fat" box. This is not an either or proposition.
On the above, most studies of this nature are actually comparing adequate vs. inadequate protein intake, not low fat vs. low carb per se.
I'm curious as to what the average "threshold" might be in terms of how low your carb intake has to be to experience adverse mood.

Take Home Message

Instead of confining yourself to either low carb or low fat diets, enjoy good, whole foods and indulge on refined carbs sensibly. Get adequate fats and proteins, ample veggies and fruit and try not to worry too much about whether your food choices are "low in carb" or "low in fat". Further, whichever route towards better health you choose, commit to something that works over the long term.

7 Comments

Spectra on 24 Nov 2009

I don't consider my diet extremely low carb, but I don't eat many refined carbs. I eat mostly whole grains, fruits, and veggies as my carbs and I wouldn't say that I was "crabby". If anything, I'm usually in a great mood and I'm rarely hungry.

Jody - Fit at 52 on 24 Nov 2009

I am like Spectra.. BUT, if I went low carb like the definition of a low carb/high protein diet, I would be cranky cause I do like the carbs I eat & I like my whole grain & healthy breads!

To each their own. If you like carbs, a low carb diet will most likely make you grumpier but if you like that plan, you will be happy. As we always say, find something you can live with for life!

shedev on 24 Nov 2009

If you are "randomized" into group and low carb is not a good fit, then of course you will be grumpy. The study should be done using people who choose to be in each group.
Ive been happily low carbing for a year now. No diet will make all people happy, the trick is to find one you can stick to easily and you will probilly not be grumpy.

Paul Bowers on 24 Nov 2009

actually, if you read the study you'd see that the low-carb group's mood values were back to baseline at the end of the study; so no, they weren't any more grumpy than they were at the start of the study. also, the researchers failed to check if the participants were actually following their prescribed diets. the 20-40grams/cho/day diet would have left the adherers in ketosis, which could have been randomly measured; but they didn't do it.

i seriously doubt people who weren't familiar or accustomed to low-carb eating would have maintained that strict of a diet for a year. in fact, i bet they lost most of their weight in the first 2 months (coinciding with mood improvements), and slowly moved back to their "normal" way of eating (i.e. higher carb), coinciding with the regressing of mood values. if you look at the "low-fat" diet , it was pretty close to the standard american diet (SAD) in terms of macronutrient composition (30% fat, 46% cho). so the "low-fat" diet would be much closer to the participants natural diet, and therefore much easier to maintain.

Rapunzel on 25 Nov 2009

I think everyone's a bit grumpy at the beginning of a "diet," or when making any major lifestyle change but over time your moods will level out. It's just getting through those first couple of weeks when you want to rip someone's head off for a piece of bread!

Barry on 25 Nov 2009

As usual, it depends. Some people experience mild euphoria from low carbing. They get deep, uninterrupted sleep, and just feel great all around. Others find just the opposite. I happen to be both. I can low carb and feel amazing. High carb works fine too, but sleep isn't as good and I don't get the 'high' that I get from low carbing.

Pater Rolf Hermann Lingen on 27 Nov 2009

"Low carb" is in essence only a - very bad - ideology. Calories make you fat.
And if you carefully read Atkins (or other prophets), you find that key elements of "low carb" are in fact key elements of any successful diet: Stop eating when you are full, make some sport etc.

However, one of the worst aspects in the "low carb" theatre is the missing distinction between sugar and other carbs.
Remember: At least 50% of your daily calorie intake should be from carbs (30% fat / 15% prot), but less than 10% should be from sugar.
Therefore, nutrition information are incomplete if not misleading if the amount of sugar in the carbs is not mentioned.
And yes, whole grain products are far better then excessively refined carbs.