Can De Novo Lipogenesis Make You Fat?

I ran across Don Matesz’ video where he cites the O. Lammert et al paper, Effects of isoenergetic overfeeding of either carbohydrate or fat in young men, to suggest that DNL can make you fat. More specifically, Matesz says the study refutes the claims of HCLF advocates (Durianrider, Dr. John McDougall) that you can’t get fat from all-the-carbs-you-can-eat.

In the study, normal weight males ate about +1200 extra calories per day above their habitual diet (@ 78/11/11 low-fat macros) for 21 days. In the end, the analysis estimates that the average subject produced only 10g fat per day via hepatic DNL, or 16g/day from total body DNL (adipose + hepatic + muscular sources, etc.).

But these numbers are in line with the HCLF diet claims, which say even if you continually overeat a massive amount of carbs, DNL will only produce “in the low 10’s” of fat grams per day. In fact, one of the paper’s authors is professor Marc Hellerstein, who’s UC Berkeley lab has studied DNL for decades. These results don’t change the picture of DNL as a minor contributor to fat accumulation in the scheme of things.

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Me @ 77 kg

IMG_2462This is me after Sunday’s 100 km ride with Moment Cycle Sports. Yes, I wear jeans, a t-shirt, and a backpack, and ride my fixie with the roadie clubs around town. I weigh 77 kg now, and my ultimate goal is around 70 kg. I was a wreck 16 months ago @ 105 kg.

I got a post-ride smoothie at the new Juice Alchemy on 5th & Spruce. I’ll probably start drinking more fruit & veggie juices and smoothies now, since watching Durianrider and Freelee on YouTube.
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Wheat Belly Diet

IMG_2271Perpetual thanks to Dr. William Davis for establishing the six bagel stack as a dietary icon. When I think of Wheat Belly, it’ll usually put me in the mood to pick up half a dozen bagels. They have a special at Einstein Brothers, where six bagels plus a half-pint of spread costs $9 USD. The bagels totaled to about 630g, so it’s a reasonable price.

I was really hungry after back-to-back spin classes this morning, and I quickly finished four of the bagels. They were just-baked warm and delicious! I’ll save the last two for after dinner, which will probably be Taiwanese noodle soup again.

Yes, if I eat a stack of bagels everyday, I’ll lose weight. It’s not magic, it’s just a low-fat diet.

(If you really want to do the math: I burned about 1600 calories in spin today. Maybe 60% of that was from fat, so I burned about 100g of fat from adipose stores. I’m pretty sure my post-workout carb meal was used to replenish glycogen stores, and almost no fat was created by DNL. But, even if 5% of the bagel carbs were converted to fat, that’d be (5%)(4/6)(630g bagel)(2.75 kcal/g bagel)(g carb / 4 kcal) = 14 of fat. No problem. I’ll burn 14g of fat sometime in the 6-8 hours before dinner.)

Boxes of Cereal

IMG_2269Lately I’ve been eating about a 1/2 box of cereal a day, along with about a pound of bread, and a bunch of tortillas. Before I learned about de novo lipogenesis, and how excess carbs are not easily turned into fat, I thought this would be a recipe for instant weight gain. I didn’t know it was just the dietary fat that got stored in our adipose tissue, while the carbs are just stored as glycogen, or burned off.

Plus, I didn’t know that these “carbs” contained all the protein I needed. I probably would have added some meat, afraid of being protein deficient. Of course, that meat just contains a bunch of fat that my body would store, and I’d get fat. Then I’d probably blame the “carbs”, because that’s been the popular message for the last 15 years.

Nowadays, I think of the bread and cereal as “carbs and protein” that’s fat-free. Basically, most starches contain about 12% protein, by calories. So, if I eat about 3000 calories of bread, etc., it’ll contain (3000 kcal)(12%)(g protein/4 kcal) = 90g of protein. That’s way more than I need, which is at most (1.2 g protein / kg of body weight)(77 kg) = 92g.

The beauty of eating almost no fat is that I don’t bother even thinking about calories anymore, let alone count them. I just eat the cereal and bread until I’m full. Then I probably eat some more cereal out of the box while watching tv on the sofa. No problem. My body will top off its glycogen stores, then burn off the rest.

I didn’t ride the bike on Monday or Tuesday, so my glycogen stores were completely maxed out for tonight. When I started my ride, my legs felt very strong. (Normally, they’re tired from day-after-day riding.) I rode my usual 5th Ave hill reps, and I PR’ed the 5th Ave Cedar to Laurel segment, taking 3rd overall with a 1:57 (out of 770 riders).

The biggest problem with constantly eating carbs is that it probably forfeits some opportunities to burn fat. I might return to eating more vegetables and lower calorie density starches like potatoes. But for the last few weeks, I’ve pounded down unlimited refined carbs (bread, noodles, and tortillas), and still lost weight. That’s a nice lesson to learn.

Brioche Loaf

IMG_2256When I get on the road at lunchtime, I’ll often pick up a loaf of bread to eat while I drive. I tried this brioche from Bread and Cie for the first time, expecting it to be really good. But it was drier than I thought it would be, as I expected the egg and sugar to make it really delicious. They must really try to make this healthy, since the nutritional info claims only 25g of fat for the whole loaf.

Anyways, I ate half the loaf driving to my destination, and the rest on the way back home that night. I also ate more bread, tortillas, and noodles. I always try to keep the fat intake below 50g/day, which means you have to check all labels and know all the ingredients in your food. Luckily, you don’t have to count calories, nor worry about whole grains, or that “carbs make you fat”. Who’s afraid of a loaf of bread?

Gary Taubes: “Carbs Literally Make You Fat”

Gary Taubes is so obsessed that “carbs make us fat”, that he thinks we could (should) eat unlimited fat, as long as we don’t eat any carbs. Who the ^#%$ wants to do that? Sure, I like bacon and eggs, but I’d rather eat sensibly than follow some tortuous ketogenic diet that doesn’t work (see below).

I prefer to eat low-fat (< 10% of calories), knowing that I can eat unlimited carbs, exercise moderately, and not risk gaining fat. This is because the body can't readily turn carbs into fat (de novo lipogensis is slow). However, any excess dietary fat will be quickly stored as body fat.

Gary Taubes takes the same understanding of the body’s mechanisms (that we preferentially burn dietary carbs and store excess dietary fat), but reaches a different conclusion. He reasons that if you don’t eat any carbs, then you can’t store any fat. WTF?! How do you make that conclusion? This logical error is called the fallacy of the inverse (If A, then B. Therefore, if not A, then not B. Not!) Here, A = “overeating carbs AND fat”, and B = “we become obese”. So “overeating fat BUT eating no carbs” is not A, therefore not B, and we don’t become obese. Not!

Some people realise this can’t really be true, and aren’t surprised when they hear about people (like Jimmy Moore) gaining weight on a ketogenic diet (< 30g/day carbs). That's exactly what a caller to Sean Croxton's Underground Wellness podcast asked (could you over-eat fat, without any carbs, and not gain weight?). Here’s Gary Taubes’ response (starts at 4:00):

… but I do not believe you can get fatter [no matter how much fat you eat, when you eat no carbs], and for most people, probably some huge proportion, 80% – 90%, if you’re not eating carbs, your’re going to lose weight, you’re not going to gain it.

So to me, its the carbohydrates that literally make you fat. You will store the fat that you eat. See, what happens when you eat the carbs and your insulin levels go up, you store the fat, the dietary fat, while you burn the carbs. And if your insulin levels stay up, you never let that dietary fat that you stored out of your fat tissue. So the carbs are still the problem, even though the fat is being stored first.

So he understands the well-known “fat-sparing” effect of eating carbs. Carbs are preferentially burned while the fat is stored. So most reasonable people eat low fat to minimize its storage. (Our bodies were made to store fat. It’s a great survival feature.) But Gary Taubes thinks we can trick the body into not storing excess dietary fat, by not eating any carbs. Good luck with that.

Then he goes on:

And because of that, we’ve been told, “Well, since we’re storing the fat and burning the carbs, if you don’t eat the fat, or if we eat less of it, we’ll store less of it.” But the carbs are controlling how the fat tissue is holding on to the fat, and whether it’s releasing it to be burned later.

So the carbs are basically what’s regulating the insulin and the insulin is regulating the fat and the dietary fat is only a problem if you’re eating a high carb diet.

He’s saying that low-fat diets don’t work, because carbs never let the fat out of the adipose tissue. But, there are plenty of times where the body burns fat, like in between meals, during moderate exercise, while you’re sleeping, etc. Sure, if you constantly keep eating, you won’t access your fat stores, but in most normal people, adipose tissue is metabolically active. Excess fat goes in when eaten, and comes out as needed. (Hey, what would happen if you didn’t eat any excess dietary fat?)

Argh. You know, if you like bacon and eggs, then eat them. If you want to eat ketogenic, then good for you. And if you want to believe that carbs make you fat, no matter what the science says, then hopefully the low-carb approach works for you. But if you go around arguing that there’s a metabolic advantage to eating no carbs, please try listening to reason occasionally.