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Low-Carb or Keto Diets and Weight Loss for Teenagers

Are you going low-carb and want to bring the whole family in? Or are you a teenager looking for weight loss (or an acne cure, or help with mood and energy levels) and interested in a low-carb or ketogenic diet?

Teenagers do have some different dietary needs than adults, but there are quite a few studies showing that low-carb diets are relatively safe and effective – at least in the short term. Here’s a look at the research on low-carb diets for older children and adolescents.

Are low-carb diets safe for teenagers?

Anyone who’s still growing – and yes, if you’re 17, this means you! – should stop at a doctor’s office first thing before trying any kind of sudden diet change. We’ve covered how starvation diets can mess up adults, but they’re even worse for bodies that are still developing. Going hungry when you’re young can actually make you more prone to gain weight later in life.

But given that a lot of doctors are predisposed to be skeptical of low-carb or Paleo* diets, here are some studies that you might read through or even bring in to talk about.

*Speaking of which, it might actually be helpful not to even mention “Paleo” at all – just say that you want to eat (or transition the family to eating) more unprocessed foods with lots of vegetables, complete proteins, and olive oil and less sugar and refined flour. That’s absolutely true, and it sounds a lot more “normal” to doctors who might otherwise get freaked out by the name “Paleo” and make silly assumptions about what you’ll be eating.

Studies on low-carb diets in teenagers

Weight loss – with dramatic individual differences

This study looked at a very low-carb diet (the subjects were instructed to stay under 20 grams per day for the first two weeks, and under 40 grams after that, so basically keto). This was a small study, with just 11 subjects in each group. The subjects in this study were aged 9-18, with an average age of 14-15.

Over 12 weeks, the low-carb group lost more weight and didn’t see any adverse effects in their blood cholesterol levels. But the interesting thing is that if you actually go into the study and look at the results, they were basically similar for both groups except that 3 kids in the low-carb group had totally fantastic results that skewed the average for the whole group. This really suggests that the average teenager might not see a huge difference, but that some teens might have dramatically better results with low-carb.

As for safety, the most common side effects in the low-carb group were constipation/diarrhea and headache. Not fun, but not particularly dangerous.

No significant difference between low-carb and low-fat by 36 weeksKetogenic foods

Another study looked at severely obese adolescents (average age 13-14) – the teens ate either a high-protein/low-carb diet or a low-fat diet for 36 weeks, with check-ins at weeks 13, 24, and 36. This was another small study, with just 33 teens completing the whole 36 weeks.

By week 36, the researchers found that teenagers in both groups lost a significant amount of weight, but they didn’t find any difference between the low-carb and low-fat groups either in weight loss or in hunger/fullness ratings. Neither group had any significant decline in bone density. Both groups also saw improvements in their blood lipids, with the low-carb group enjoying a particularly strong reduction in triglycerides. (Read: going low-carb/high-fat won’t send anyone’s cholesterol levels through the roof.)

The researchers concluded that the low-carb diet was basically safe, or at least “without serious adverse effects.”

Insulin sensitivity improved on low-carb

This study in 55 adolescents (ages 12-18) with obesity found that low-carb and low-fat diets delivered roughly the same weight loss, but that low-carb diets improved insulin sensitivity where low-fat diets didn’t. Insulin sensitivity is a good measure of how well your body processes carbs, so that’s a good sign for improving blood sugar control. (Read more about low-carb diets and insulin sensitivity here).

And one more study on weight loss

Take this study with a grain of salt because there was no control group, but it is a bit bigger than the others, which is cool. The researchers took 63 children ages 12-18 and put them on a low-carb diet (under 50 grams of carbs per day) for 6 months. Only 38 actually finished out the 6 months, but of those, most (32) lost a significant amount of weight, ranging from 5.5 kilograms (12 lbs) to nearly 24 kilograms (53 lbs). Again, the diet was safe and the researchers didn’t report any serious problems.

Putting the studies together

These studies don’t all agree – some of them found that low-carb diets were better than low-fat; others didn’t find a difference – but none of them reported any serious side effects and all of them had low-carb at least tied with a typical low-fat “healthy” diet for teenagers. At the very least, this suggests that low-carb diets are just as good as classic weight-loss diets, and just as safe. The evidence indicates that for teenagers, low-carb diets won’t send their cholesterol skyrocketing into heart-attack land, or make their bones disintegrate, or whatever else people are afraid of.

Judging from the drop-out rates, low-carb diets don’t even seem to be any harder for teenage patients to follow than low-fat diets – which is to say that a lot of people will lose some weight on them and then most of those people won’t maintain their weight loss in the long term, because very few people can do that on any kind of diet at all.

The really interesting part might be the study showing such dramatically different results for different individuals. Some teens might do really well on low-carb, while others might not. It’s worth noting that studies like this one highlight the benefit of restricting junk carbs, without needing to restrict total carbs very much (that study diet was 45% whole-food carbs, which is pretty high by Paleo standards – and when teenage boys ate it, they lost weight and their acne improved). Low-carb diets definitely aren’t the only solution, and you can even do Paleo without going low-carb: just eat Paleo-friendly starches like sweet potatoes, white potatoes (really!), winter squash, and root vegetables. Especially for growing teenagers, finding the right diet might take a few tries and it might change from year to year.

Weight loss for teenagers is really tricky: got any great tips or stories to share? Let us know on Facebook or Twitter!