Flashback Friday: Paleo Diets May Negate Benefits of Exercise

Much of the low carb and paleo reasoning revolves around insulin. To quote one random blogger, “Carbohydrates increase insulin, the root of all evil when it comes to dieting and health.” So because carbs increase insulin, we should stick mostly to meat, which is fat and protein—no carbs, so no increase in insulin, right? Wrong. We’ve known for half a century that if you give someone just a steak, no carbs, no sugar, no starch–their insulin goes up. Carbs make your insulin go up, but so does protein.

In 1997 an insulin index of foods was published, ranking 38 foods on which stimulates higher insulin levels. What do you think causes a larger insulin spike: a large apple and all its sugar, a cup of oatmeal packed with carbs, a cup and a half of white flour pasta, a big bunless burger—no carbs at all–or half of a salmon fillet? The answer is the meat.

They looked only at beef and fish, but subsequent data showed that there’s no significant difference between the insulin spike from beef, versus chicken or pork—they’re all just as high. Thus, protein- and fat-rich foods may induce substantial insulin secretion. In fact, meat protein causes as much insulin release as pure sugar.

So, based on their own framework, if they really believed insulin is the root of all evil, then low carbers and paleo folks would be eating big bowls of white spaghetti day in and day out before they’d ever touch meat.

Yes, having hyperinsulinemia–too high levels of insulin in the blood–like type 2 diabetics have, is not a good thing, and may increase cancer by like 10%. But if low carb and paleo people stuck to their own theory, if it’s all about insulin, they would be out telling everyone to go vegetarian, as vegetarians have significantly lower insulin levels, even at the same weight. It’s true for ovolactovegetarians. It’s true for lactovegetarians and vegans. Meateaters have up to 50% higher insulin levels.

Put someone on a strictly plant-based diet–man, woman, young, old, skinny or fat–and you can significantly bring their insulin levels down within just three weeks on a healthy vegan diet. And then just by adding egg whites back to the diet, you can boost insulin production 60% within four days.

What if you take people and add carbohydrates, double their carbohydrate intake? You can bring their insulin levels down. Why? Because they weren’t feeding people jellybeans and sugar cookies; they were feeding people whole plant foods, lots of whole grains, beans, fruits, and vegetables.

What if you put someone on a very low-carb diet, like an Atkins diet? Low carb advocates assumed that it would lower insulin levels. Dr. Westman is the new Dr. Atkins, after the old Dr. Atkins died overweight with, according to the Medical Examiner, a history of heart attack, congestive heart failure and hypertension. But Dr. Westman was wrong. No significant drop in insulin levels on very low carb diets. What they got is a significant rise in their LDL cholesterol levels, the #1 risk factor for our #1 killer, heart disease.

Atkins is an easy target, though. No matter how many new, new, extra new Atkins diets that come out, it’s still old news. What about paleo? The paleo movement gets a lot of things right. They tell people to ditch dairy and doughnuts, eat lots of fruits, nuts, and vegetables, and cut out a lot of processed junk. But this new study’s pretty scary. Took a bunch of young healthy folks, put them on a Paleolithic diet along with a Crossfit-based, high-intensity circuit training exercise program. Now if you lose enough weight exercising you can temporarily drop your cholesterol levels no matter what you eat. You can see that with stomach stapling surgery, tuberculosis, chemo, a cocaine habit—just losing weight by any means can lower cholesterol, which makes these results all the more troubling. Ten weeks of hard-core workouts and weight loss, and LDL cholesterol still went up. And it was even worse for those who started out the healthiest. Those starting out with excellent LDLs, under 70, had a 20% elevation in LDL, and their HDL dropped. Exercise is supposed to boost your good cholesterol, not lower it. The Paleo diet’s deleterious impact on blood fats was not only significant, but substantial enough to counteract the improvements commonly seen with improved fitness and body composition. Exercise is supposed to make things better. Put people instead on a plant-based diet and a modest exercise program—mostly just walking-based, and within three weeks they can drop their bad cholesterol 20%, and their insulin levels 30%, despite the 75-80% carbohydrate diet, whereas the paleo diets appeared to negate the positive effects of exercise.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.

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Images thanks to picaidol via Pixabay and Pascal, Lonnie, and sriram bala via Flickr.