Dear Mark: Does Eating a Low Carb Diet Cause Insulin Resistance?
Despite all the success you might have had with the Primal way of life, doubts can still nag at you. Maybe it’s something you read, or something someone said to you, or a disapproving glance or offhand comment from a person you otherwise respect, but it’s pretty common when you’re doing something, like giving up grains, avoiding processed food, or eating animal fat, that challenges deeply-and-widely held beliefs about health and wellness. It doesn’t really even matter that you’re losing weight or seem to be thriving; you may still have questions. That’s healthy and smart, and it’s totally natural.
A question I’ve been getting of late is the effect of reducing carb intake on insulin sensitivity. It’s often bandied about that going low carb is good for folks with insulin resistance, but it’s also said that low carb can worsen insulin resistance. Are both true and, if so, how do they all jibe together? That’s what the reader was wondering with this week’s question:
Hi Mark,
I’ve been Primal for a few months now and love it. Lowering my carbs and upping my animal fat helped me lose weight and gain tons of energy (not too shabby for a middle-aged guy!). However, I’m a little worried. I’ve heard that low carb diets can increase insulin resistance. Even though I’ve done well and feel great, should I be worried about insulin resistance? Do I need to increase my carb intake? I always thought low carb Primal was supposed to improve insulin function.
Vince
Going Primal usually does improve insulin sensitivity, both directly and in a roundabout way. It improves directly because you lose weight, you reduce your intake of inflammatory foods, you lower systemic inflammation (by getting some sun, smart exercise, omega-3s, and reducing or dealing with stress), and you eat a wide variety of plants, animals, and herbs with anti-inflammatory and/or insulin-sensitizing effects. It improves indirectly because you are removing the thing that exacerbates the condition – large amounts of carbohydrates – and thus avoiding the negative effects. You might still be insulin resistant, but since you aren’t cramming your face with carbs anymore, you don’t notice it.
And sure enough, the weight loss studies indicate that during weight loss, very low carb diets improve insulin sensitivity:
- In overweight women, a diet with less than 10% of calories as carbs improved insulin sensitivity, while a 30% fat, low-fat diet reduced it.
- In obese, insulin-resistant women, both high-fat and high-protein low-carb diets reduced insulin resistance, while the high-carb diet was not as effective.
- In obese kids, a very low carb diet was able to reduce indices of insulin resistance along with bodyweight and body fatness.
However, going very low carb – to around or below 10% of calories, or full-blown ketogenic – can induce ”physiological” insulin resistance. Physiological insulin resistance is an adaptation, a normal biological reaction to a lack of dietary glucose. As I’ve said in the past, the brain must have glucose. It can use ketones and lactate quite effectively, thus reducing the glucose requirement, but at the end of the day it still requires a portion of glucose. Now, in a low-glucose state, where the body senses that dietary glucose might not be coming anytime soon, peripheral insulin resistance is triggered. This prevents the muscles from taking up “precious” glucose that the brain requires. The brain’s sensitivity to insulin is preserved, allowing it to grab what glucose it needs from the paltry – but sufficient – levels available to it.
It appears that weight loss is the deciding factor, and since low carb diets tend to be more effective at inducing weight loss in subjects, they also tend to be better at reducing insulin resistance in insulin-resistant, overweight people. Once you’re lean and weight stable, though, very low carb diets (less than 10% of calories from carbs) can reduce insulin sensitivity. This is normal and totally necessary in the context of a very low carb diet. If we didn’t become insulin resistant while eating very low carb, our brain wouldn’t be able to get the glucose it needed to keep us alive.
Okay, but what about dietary amino acids? If our tissues are insulin resistant on very low carb, and insulin also promotes muscle protein synthesis, doesn’t that mean the amino acids from the protein we eat have a harder time getting into our muscles? You might think that, but that’s not how it plays out in the real world. In actual clinical trials, low carb diets are consistently linked with preservation of lean mass during weight loss. People on low carb diets lose more fat and less lean mass.
Muscle glycogen stores may be depleted, but if you want to fill those back up, you can do so quite effectively post workout, even when you’re low carb and otherwise physiologically insulin resistant. A bout of weight lifting, sprints, or even just regular walking can improve your ability to tolerate and handle glucose by making you more insulin-sensitive. This holds true even for the otherwise insulin-resistant.
In the end, insulin resistance on very low carb appears to be a physiological adaptation to spare glucose for the brain and prevent your muscles from gobbling it up. I see no reason to think it’s a pathological problem, especially given the droves of success stories on this site and others from people who have lost weight, torn up prescriptions, boggled the minds of doctors, and reclaimed their once-failing health through a low-carb Primal way of eating and living. I could be wrong, and time will tell, I suppose, but I doubt it.
Besides, there are far more pressing potentially negative influences on insulin sensitivity that we can be addressing, like:
- Sedentary lifestyles. And I’m not just talking about strength training and high-intensity sprints; simple, basic low-level physical activity, like walking on a daily basis, can have a powerful effect on insulin resistance.
- Unchecked and out-of-control appetites. Weight gain and an excess of energy (that the mitochondria can’t handle for whatever reason) are potent causes of insulin resistance.
- Environmental pollutants and toxins like BPA and various fungicides can have negative effects on insulin sensitivity.
To sum up, I don’t think you need to worry about insulin resistance as long as you’re still losing weight – which you appear to be doing – since weight loss exerts a powerful effect on insulin sensitivity. However, once you’re lean, or have stalled without changing anything, moving back toward the 100-150 Primal carb gram range will keep your insulin receptors “honest” without causing weight gain (and it may even jumpstart weight loss again). Lifting heavy things, sprinting every once in awhile (in a manner suitable for your physical limitations), and doing lots of slow moving will also keep you insulin-sensitive, particularly after the physical activity.
Thanks for reading, folks, and I hope I cleared this up for you without raising too many more questions. Let me know your experience in the comment section.
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Posted By: Mark Sisson
****My question is, could this be accurately considered a sprint, and would it help me lose wight?
Work out fasted, and don’t eat after the workout for about 1-2hrs (you could if you want to bulk up, but not if you want to lean out.) You can also ingest some black coffee with Yohimbine to help the process (but yohimbine should be on an empty stomach, or else it won’t work.)
No, those aren’t sprints, sprints are running at top speed for a short while (until you’re winded). You could do sprints in an HIIT form, that is, run in bursts until you’re winded and feel the burn, rest for a few minutes and do it again 4x-5x.
See the leangains site for more info about that.
I eat 1-2 kilograms of sweet potato everyday, along with chicken breast. Do you think that is too much?
that’s about 150kcals per kg of raw sweet potato in carbs right there, it is a lot, but if you’re not trying to lose fat, it’s ok — as long as you don’t ingest other carbs. But you probably want to stay under 1kg.
And wouldn’t you want to eat a big salad as well? So why limit yourself to such huge portions of sweet potato, and why eat the same thing every day? That’s not healthy, you’re hitting the same metabolic pathways day in and day out.
Also, why just the chicken breast? You do know there’s fish, shellfish, grassfed beef/bison/lamb, and especially their livers out there.
Eat different stuff every day, and even do IFs once in a while.
I’m trying to gain weight, around 10 kilograms. I eat tuna as well and steak 3 times a week.
I was wondering what are some alternatives to gaining weight following paleo principles. I need something relatively cheap and calorie dense-like sweet potato (although that makes me somewhat tired following large portions
chicken breast?! Gross
1-2 kilos of sweet potato sounds like a lot unless you’re training competitively or building houses by hand from scratch. But if you’re thriving off it and feeling great, see how far it’ll take you!
Those omega-3s taste uber after not having them for a while.
I wish stores sold salmon juice by the bottle.
And remember, they’re good for your brain, so eat fish and you’ll acquire sardine wit.
I don’t think an extremely low-carb (ketogenic) diet over a long period of time is a good idea. Eliminating sweets and grain products is an excellent idea. But eliminating fresh vegetables and small amounts of fruit (also considered carbohyrates) in favor of nothing but protein and fat is like throwing the baby out with the bath water. It eliminates many of the vitamins and nutrients the body needs for healthy functioning.
Incidentally, according to my very experienced homeopath, low-carb is the best thing out there for normalizing blood pressure. This means protein, healthy fats, AND vegetables, along with small amounts of whole fresh fruit.
Who said you can’t have fresh fruit and veggies? If you search for the shopping list on this site you will see that there is a wide range of fruits and veggies you can have. The fruits listed have a low-glycemic index that is important for this new way of eating.
I realize that. I’m going by the number of comments I’ve read (on this and other web sites) from people who seem to think that if less is good then none is better. Actually, all fruit and veggies have something to offer nutritionally. For more rapid weight loss, sticking with low glycemic is best.
I disagree completely. I’m fairly sure you can get all the vitamins and minerals you need out of a well formulated VLCKD.
If you eat offal, bone broth and such. I haven’t run any numbers but that’s my gut. For those that like vegetables/fruits it may not be ideal but I think its possible.
At this point since I don’t have numbers I can’t prove you wrong but my gut says you are.
From eating fish, bone broth, and different kinds of pastured meat that covers at least all the amino acids. That I’m fairly sure of.
To get some of the vitamins that are destroyed by cooking (e.g. Vitamin C), you have to eat at least some of your animal products raw, or at least very rare. (which I do)
That claim does coincide with what I have read. It does appear to be possible to get 100% of your nutritional requirements from animal sources. In fact, I think that a combination of pastured eggs and large insects (grasshoppers, roaches, waterbugs, etc.) eaten raw would do it. Personally, I’m not much for eating insects or raw eggs, so I choose to supplement with dark green and purple veggies, and occasional fruit. And some modern-day supplements.
It is also possible to get 100% of your requirements from a vegetarian diet — with a great deal of effort. I don’t think it’s possible to do so with a vegan diet (which I regard as an extreme eating disorder) without supplementation with synthetic vitamins.
Why insects at all though? Were you just saying that you’ve read its possible with insects? I’m fairly certain it would be possible with just beef, pork, chicken with some organ meat included.
Add in fish and bone broth. While eating some raw or close to raw…should get everything. Whats in insects that you couldn’t find in one of the others?
It would be great to see Mark post about the possibility of getting everything you need as far as vitamins, minerals, aminos, etc. from animal products (including delicious organs)…and just eating veggies for fiber’s sake.
I am curious about Antioxidants as well. I know vegetables and fruits are touted for their antioxidants.
Can you get plenty of them from animal products? I think so but I don’t know very much about that. A properly formulated VLCKD would be anti-inflammatory for sure though.
Hey Mark do a post please thanks
I’ve been primal since end of Nov 2011–about 9 months. After years of highish triglycerides of 150 and above, I just got my trig results today: 74!
Down over 10 pounds from last year, too. (Now 112 lb, but I’m very small-framed. I can do pull-ups and everything, quite muscular now. The nurse commented this morning, “Nice muscles!”)
That’s after a cruise last week where I drank plenty o’ wine, rum, tequila… and even had some brioche and desserts and whatnot.
Since triglycerides levels correspond to the body’s handling of blood sugars, I’d say this lifestyle has done wonders for me. My family history features high trigs.
I eat fruit each day with my daughter, along with ample veg and meats. I do take an omega-3 once a day, too. The main thing I changed was to drop grains from my daily diet.
Last year, I was all about the rice and beans and avoiding animal fats. Not this year, and the HDL went up from 50 to 77, too. I’m very surprised and pleased today, so I’ll not be sweating insulin resistance any time soon.
Have you read Body By Science? Written by someone who believes in Paleo. Awesome workout book. For anyone not just men.
I loved The Art and Science of Low Carbohydrate Living/Performance too.
On a well formulated Low Carbohydrate Diet you can perform perfectly well being fat adapted. You have a much larger fuel reserve than a carb burner.
http://www.meandmydiabetes.com/2012/08/11/western-states-100-low-carber-wins-ultramarathon-steve-phinney-and-jeff-volek-study/
Pretty cool article on low carber winning an ultra-marathon.
About the protein, this is how I do it…
I generally eat approx 75% of my lean body weight with up to 30gm of carbs in the form of fruit/veggies per meal. The rest come from plenty of fat.
If I eat 40gm or more carbs per meal I get sleepy and tired.
The only time I eat 1 – 1.5gm of protein per pound of lean body weight is after heavy training like weight lifting, sprint etc for the last 24 hours. Then, it is back to 75% of my lean body weight. Works well every time.
Need help and advice:
About 5 months into a very low carb and high fat diet, my usually low BS of 80-95 shooted to 174, then 190 and then 204… I was wondering if its due to the increased protein or something else.
I eat natural foods and no packaged or processed food… no fruit, no hidden sugars in anything I eat…
My weight is 118lbs, 5ft 3ins and normal blood pressure.
Comments please
If I eat around 50g of Carbs a day am I allowed one or two beers a day? Please?
Interesting article… starting to make sense. I went primal about a year ago. I went really low carb. Didn’t lose ANY weight. Then, as soon as I added carbs back in, I gained 50 pounds just as quick as anything. I’ve been going to the Doc. Tests say my glucose is spot on, but I have all the symptoms of PCOS. The symptoms all stem from glucose resistance.
This article explains what has happened to me. I was really confused how I could become glucose resistant after eating such a low carb diet.
I do Leangains and carb cycle. The 100-150 grams of carbs on the curve is ridiculous and has no scientific basis. I do 35 grams of carbs on rest days and 270-ish on training days and I’m lean. Eating too much fat, too much carbs or too much protein will make you fat, not good carbs for active people.
No, I’m not a sugar burner. I burn fat and glucose like all people.
This will greatly depend on what you do on your training days. Do you do crossfit type workouts that burn glycogen/glucose? Then yes, carbs are necessary. I’m assuming at 270g of carbs on training days means you’re doing some intense stuff. Whatever the case, it’s working for you so keep doing it!
The 100-150 amount is meant for maintenance and doesn’t include an activity factor.
He says in his posts that if you are more active having more carbohydrates works.
It is not necessary though.
Read The Art and Science of Low Carbohydrate Living/Performance for more details
Sure you can do just fine on carb cycling, but I don’t think its at all necessary.
High insulin sensitivity ensures that the body responds to minimal levels of insulin and is able to successfully maintain blood glucose levels in the normal range. Decreased insulin sensitivity could result in hyperinsulinemia and hyperglycemia. The excess insulin in the blood stream can damage the blood vessels, increase risk of heart disease, blood pressure, obesity accelerated ageing and even cancer. The most universal cause of insulin resistance is believed to be aging but other lifestyle factors such as poor dietary habits and lack of physical activity also play a role. The good news is that you can improve insulin sensitivity by adopting specific measures associated with diet and exercise. Here’s how http://lovefitnesseducation.com/2012/11/09/how-to-improve-your-insulin-sensitivity/
I found that eating small “mini meals” made me insulin resistant. When I switched over to eating 2 meals a day, the weight cam off quite nicely.
Dear Mark, do you know what levels of fasting insulin are involved with so called “physiological insulin resistance” ?
In this study below the low carb group dropped fasting insulin from 10.7 to 7.1 over 12 wks with 4% carbs.
http://www.nutritionandmetabolism.com/content/pdf/1743-7075-3-7.pdf
Is the mentioned effect coming showing up at 10, 7.5, 5 mU/L or lower? Have anything at the lower levels shown any harmful effects, or is it mere redirections to critical organs at very low calorie intake? Looking fwd to your reply. Also what ketone levels were involved?
If you can include a link to the study that showed the insulin resistance response, my question about the levels would easily be clarified!