What Is The Fate Of Excess Carbohydrate? Does It Turn Into Fat?

Does eating carbohydrate, starch, make us fat? The short answer is “No.” The caveat is “No, as long as the diet is not also high in fat.”

The carbohydrate we eat has many fates. One fate, after it’s broken down into glucose, is energy production. That’s its primary fate. Its next fate is the replenishment of glycogen. (Glycogen is a form of energy storage. It’s made up of many units of glucose strung together.) A pound of glycogen stores about 1800 calories. We can store several pounds of glycogen in the body – in liver, muscle, even fat cells store glycogen. We can store A LOT of calories from the carb we eat as glycogen without turning it into fat. Fat production does occur, but it does not rank high in the body’s use of glucose.*

In humans there is little lipogenesis [fat production] from glucose under normal conditions.

What is the fate then of excess glucose?

1. It warms the body:

Thermogenesis [heat production] can help eliminate a sizeable part of the excess unused dietary glucose.”

2. It can be consumed by gut bacteria:

An undetermined part of the excess body glucose may find its way into the intestinal lumen [glucose freely diffuses across the intestinal wall, both ways], where it may be taken up and metabolized by the microorganisms.

3. It can be lost in urine: From blood, glucose travels to kidneys where it’s excreted. At one time, people tested for diabetes by tasting urine for sweetness.

People known as “water tasters” diagnosed diabetes by tasting the urine of people suspected to have it. If urine tasted sweet, diabetes was diagnosed. To acknowledge this feature, in 1675 the word “mellitus,” meaning honey, was added to the name “diabetes,” meaning siphon.

4. It can be used for fat production. But that has limits:

Excess glucose has difficulty entering cells (for fat production) if the cell has already satisfied its glucose needs. How does the cell close the door to too much glucose, which can damage the cell? By becoming resistant to insulin, a hormone which opens the door. High-caloric/high dietary-fat environments cause cells to become insulin resistant. Blood glucose then rises. That causes insulin to rise even more, leading to a cascade of largely undesirable effects. Insulin is an anabolic hormone and supports lipogenesis/fat production – but the preferred substrate or building block for fat production is fatty acids, not glucose:

Brown adipose [fat] tissue (BAT) enhanced consumption of glucose may represent a quantitatively significant possibility for rodents, but it is doubtful that in humans, with a limited BAT presence, it may represent a significant dent in the pool of excess circulating glucose, especially when BAT preferred substrate is, again, lipid.

A number of tissues, such as white adipose tissue (WAT), however, develop the ability to deactivate a significant proportion of the insulin carried by the blood, a mechanism that protects the tissues themselves of being force-fed an unwanted and not metabolizable [because of saturation of normal pathways] load of glucose.

A high-caloric diet where fat calories are in abundance can lead to chronic insulin resistance, diabetes, inflammation, high blood cholesterol, fatty liver … the very definition of the metabolic syndrome.

People do not get fat eating lots of carbohydrate. Look at the rice diet, or the potato diet. In fact, people tend to lose weight … as long as they are not pouring oil on salads and pasta or melting cheese over vegetables or eating lots of just about any animal food which contains most of the saturated fat and cholesterol in the human diet.

Whole populations have survived and thrived on diets that received most of their calories from carbohydrates – rice, potatoes, corn, wheat, barley. And they did not not have the obesity problems we have today.

Dr. McDougall says, “The fat you eat is the fat you wear.” He’s right. (This article said it more scientifically, “Dietary lipids favor their metabolic processing.”)

* Utilization Of Dietary Glucose In The Metabolic Syndrome, Nutrition and Metabolism, 2011

Another Study Demonstrates The Calorie-Lowering Effect Of Cooking Then Cooling Starch – This Time In Rice (Repost)

This photo accompanied the Telegraph article. While it’s beautiful, it somewhat misrepresents the research’s finding – that cooled rice contains fewer calories than hot rice. Does cool rice steam? Although reheating rice after it has cooled does not eliminate its resistant starch.

What happens to the starch in pasta, rice, potatoes, corn, oats, and many other starchy foods when you cook them, then allow them to cool slowly? The starch becomes resistant to our digestive enzymes. I’ve been writing about resistant starch (RS) for 10 years now so it’s probably familiar to you. Resistant starch passes through to the colon undigested and ends up feeding resident bacteria. We derive significantly fewer calories from starchy food that has been heated and cooled compared to just heated. We also derive benefit from the byproducts of the bacteria that eat the starch, e.g short-chain fatty acids and some vitamins. And, given the findings in this study, we may also derive cognitive benefit by populating our gut with beneficial RS-eating microorganisms.

Research presented at the American Chemical Society annual meeting last week described a technique for reducing calories in rice by up to 60%. You simply cook then cool the rice:

“The cooling is essential because amylose, the soluble part of the starch, leaves the granules during gelatinization,” explains [team leader Sudhair A. James]. “Cooling for 12 hours will lead to formation of hydrogen bonds between the amylose molecules outside the rice grains which also turns it into a resistant starch.” Reheating the rice for consumption, he notes, does not affect the RS levels.


RS is not broken down in the small intestine, where carbohydrates normally are metabolized into glucose and other simple sugars and absorbed into the bloodstream.

One more point. I say this often but it seems to go into the ether or something:

“After your body converts carbohydrates into glucose, any leftover fuel gets converted into a polysaccharide carbohydrate called glycogen,” [James] explains. “Your liver and muscles store glycogen for energy and quickly turn it back into glucose as needed.

People say that leftover glucose gets converted to fat. It doesn’t. It gets converted into glycogen, which is not fat.

Some headlines:

I wouldn’t call this technique “new,” would you?
New Low-Calorie Rice Could Help Cut Rising Obesity Rates, Press release from the American Chemical Society

This next title implies it’s more about the cooking. It’s not. It’s more about the cooling. By the way, this author says starch “has one central flaw: it isn’t that good for you.” The starch in potatoes, pumpkins, squashes, beans, peas, corn, carrots, barley, oats, wheat, and rice aren’t good for you. He also says that cooked potatoes are less healthful than raw potatoes. I don’t think I would ever eat a potato that wasn’t cooked:
Scientists Have Discovered A Simple Way To Cook Rice That Dramatically Cuts The Calories, Washington Post blog

Simple. Yes, it’s simple:
Simple Rice-Cooking Hack Could Reduce Calories By 60 Per Cent, The Telegraph

It’s true, eat it cold for fewer calories. But you can also reheat it if you don’t like it cold. Reheating won’t eliminate the resistant starch. In fact, the more you reheat and recool, the more resistant starch you create:
‘Eat Rice Cold For Fewer Calories’, BBC

Repost: Popcorn Has About Double The Antioxidants Of Fruits And Vegetables

Popcorn: The Snack With Even Higher Antioxidants Levels Than Fruits And Vegetables, Presented at a meeting of the American Chemical Society, March 2012

The amount of polyphenols found in popcorn was up to 300 mg a serving compared to 114 mg for a serving of sweet corn and 160 mg for all fruits per serving. In addition, one serving of popcorn would provide 13 percent of an average intake of polyphenols a day per person in the U.S. Fruits provide 255 mg per day of polyphenols and vegetables provide 218 mg per day to the average U.S. diet.

The levels of polyphenols rivaled those in nuts and were up to 15 times greater than whole-grain tortilla chips.

The hulls of the popcorn — the part that everyone hates for its tendency to get caught in the teeth — actually has the highest concentration of polyphenols and fiber.

Popcorn may be the perfect snack food. It’s the only snack that is 100 percent unprocessed whole grain.

If most of the polyphenols reside in the hulls, do we digest them enough to get the benefit? Dr. Joe Vinson, the study’s lead researcher, did a “digestion simulation”:

“We did our own digestion (research) that doesn’t use enzymes, and you as a human being have enzymes and different pH changes to digest food,” he said.

So there’s a good chance those antioxidants are getting digested and absorbed.

Popcorn is whole grain, high in fiber, low in fat, low in calories, and high in antioxidants. There’s not a lot out there that can compete with that.

Blue Jay Left Me A Gift

I think a blue jay left me a gift. I could be reading into it, but, so what. I’m going to say it’s a gift. I had been feeding these one or two jays and this morning, in the exact spot where I leave them a nut, one of them deposited this little shell. Perfectly intact. Then flew away.

Did Crows Actually Make These Gifts for the Human Who Feeds Them?, Audobon, May 2019

Crows, as members of the corvid family*, are highly intelligent creatures that make tools, recognize individual humans, and learn from one another. … They do occasionally leave behind objects like keys, lost earrings, bones, or rocks, for the people who feed them, a behavior that John Marzluff, conservation ecologist and Swift’s colleague at the University of Washington, calls “gifting.”

*Blue jays are members of the corvid family.

It’s not the first time I’ve found odd objects where I leave food for birds. I bet they’re watching me. Every time I go outside … they’re watching. Right? The world feels so crowded.

Do Zinc Supplements Increase Risk For Prostate Cancer?

While I’m visiting the relationship between vitamin supplements and disease (e.g. “Conclusions: These Results Suggest That Multivitamin Use Is Associated With An Increased Risk Of Breast Cancer”), I thought I’d throw these two up:

1. Zinc Supplement Use And Risk Of Prostate Cancer, Journal of the National Cancer Institute, July 2003

We examined the association between supplemental zinc intake and prostate cancer risk among 46 974 U.S. men participating in the Health Professionals Follow-Up Study. During 14 years of follow-up from 1986 through 2000, 2901 new cases of prostate cancer were ascertained, of which 434 cases were diagnosed as advanced cancer.

Compared with nonusers, men who consumed more than 100 mg/day of supplemental zinc had a relative risk of advanced prostate cancer of 2.29, and men who took supplemental zinc for 10 or more years had a relative risk of 2.37.

Our findings, that chronic zinc oversupply may play a role in prostate carcinogenesis, warrant further investigation.

2. Zinc Intake And Risk Of Prostate Cancer: Case-Control Study And Meta-Analysis, PLoS One, November 2016

Using a dose-response meta-analysis, we observed a non-linear trend in the relationship between zinc intake and prostate cancer (p for nonlinearity = 0.0022).

14,000 micrograms is only 14 mg. The RDA for zinc for men is 11 mg. So, not much more than the RDA may be a problem.

“Conclusions: These Results Suggest That Multivitamin Use Is Associated With An Increased Risk Of Breast Cancer”.

I have a love/hate relationship with vitamins. This study nudges me away from taking them:

Multivitamin Use And Breast Cancer Incidence In A Prospective Cohort Of Swedish Women, American Journal of Clinical Nutrition, 2010

The Swedish Mammography Cohort, 35,329 women, mean follow-up 9.5 years. Results:

Multivitamin use was associated with a statistically significant increased risk of breast cancer.


The possibility that multivitamin use may increase the risk of breast cancer is biologically plausible. A recent study (2) showed that the current use of multivitamins and minerals in premenopausal women was associated with a significant 5.3% higher mean mammographic breast density (after adjustment for potential confounders), which is strongly and positively related to breast cancer risk. Folic acid in supplements could possibly increase the risk of breast cancer. High doses of folic acid from supplements or fortified foods are of concern because synthetic folic acid is more bioavailable than folate from natural food sources and, hence, potentially more potent in promoting cancer growth .

If folic acid is responsible for the observed association between multivitamin use and a risk of breast cancer, the association may not be seen in the US population because breakfast cereals and grain products have been fortified with folic acid since 1998 in the United States.

Other constituents of multivitamins with minerals that may be associated with cancer risk include iron and zinc. Experimental studies showed that a diet low in iron (19) or zinc (20) can suppress carcinogen-induced mammary cancer in rats. In a case-control study (21) nested in a cohort of women with benign breast disease, iron and zinc concentrations in benign breast tissue were positively associated with breast cancer risk. … In the current study, there was a nonsignificant 55% increase in breast cancer risk associated with zinc supplement use among nonusers of multivitamins.

Folic acid is a real contender for the problem. Unfortunately, we started adding folic acid to flour products in the US in the late 1990s so that will mask any studies trying to determine folic acid’s contribution. Sweden doesn’t fortify with folic acid; perhaps that’s why they found an association.

Interesting that bit about diets low in iron and zinc being beneficial vis-a-vis breast cancer. Vegan diets are naturally low in iron and zinc.

Selling Cancer Screening Is Easy. Induce Fear By Exaggerating Risk. Offer Hope By Exaggerating Benefit. The Case Of Mammograms

90% of Women Appear Misinformed About Mammograms, Michael Greger MD, NutritionFacts, 21 September 2021

Most women are just being told what to do, rather than being given the facts needed to make a fully informed decision.

“Selling cancer screening can be easy,” begins an editorial in the Journal of the National Cancer Institute. “Induce fear by exaggerating risk. Offer hope by exaggerating the benefit of screening. And don’t mention harms [caused by the screening]. It is especially easy with cancer—no diagnosis is more dreaded. And, we all know the mantra: early detection is the best protection. Doubt it, and someone may suggest you need your head examined.” And they are not exaggerating, as you can see for yourself at 0:37 in my video Nine out of Ten Women Misinformed About Mammograms, when I show an American Cancer Society pamphlet that actually warns women, “If you haven’t had a mammogram, you need more than your breasts examined.”

“Screening can lead to important benefits, but it can also lead to important harms,” continues the editorial. “A big challenge is conveying the counterintuitive idea that screening does not always help—and can even be harmful. Surveys have shown that most people believe that cancer screening is almost always a good idea and few believe harm [is even] possible.” In patient education materials, “passing reference to potential harms is deceptively buried in a euphoria of benefits.”

The cancer screening test that has been studied most carefully is the mammogram. “In the past 50 years, more than 600,000 women have participated in 10 randomized trials, each involving approximately 10 years of follow-up. Given this extraordinary research effort, it is ironic that screening mammography continues to be one of the most contentious issues within the medical community.” Indeed, in medicine, there are “few fields that invoke more passion…than the question of screening women for the detection of an earlier, more curable stage of breast cancer.” Ironically, both sides accuse the media of being in the opposite camp.

This contentiousness, however, “is in itself instructive.” It should tell us something. “For context, one trial involving fewer than 150 men who were followed for less than 2 years was sufficient to convince physicians of the value of treating severe hypertension.” The benefits of treatment were just so obvious. In contrast, the fact that we’re still debating the merits of mammograms 50 years later, even after 10 trials with 600,000 women, “suggests that the test is surely a close call, a delicate balance between modest benefit and modest harm.” However, that assumes people are weighing the pros and cons objectively. Given the multibillion–dollar industries involved—from the mammogram machine manufacturers to the radiologists who read them—it may be worse than that.

Several organizations publish contradictory cancer screening recommendations. Some recommend mammograms starting at age 40 while others say 50. Some say every year, some say every other year, and some recommend that women shouldn’t get them routinely at all. “There is increasing concern about both financial and emotional conflicts of interest interfering in the generation of guidelines.” People can get so invested in the position they’ve staked out that it may cloud their judgement.

“Reasonable experts agree that the body of evidence suggests that there is some benefit to mammography among women aged 40 years…Although the benefits of mammography screening have certainly been exaggerated, this does not mean that it does not save lives or that women should not get it.” The question is, do the benefits outweigh the risks? That’s a decision each woman has to make for herself, but she can’t do that without knowing all the facts.

Women are so bombarded with information about mammograms, you’d think they would be fairly knowledgeable about them. “Yet nothing is farther from the truth…” Nine out of 10 women surveyed vastly overestimated the benefits of mammograms or had no idea. It’s not the women’s fault, though. They’re obviously being misinformed by the system. Most American women didn’t even appear to understand the basic concept of mammography screening and “believed that screening prevents or reduces the risk of contracting breast cancer” in the first place. This raises doubts about how well women are being informed. It sounds like “women are told what they should do, but without being given the facts necessary to make informed decisions…As a result of paternalism and pink ribbon culture, almost all women have a false impression of the benefit of mammography screening…Most surprisingly, those who frequently consulted their physicians and health pamphlets were slightly worse informed.” It’s as if they were anti–educated by their doctors!

The problem is that these kinds of “inaccurate and exaggerated perceptions of the benefit of screening” prevent women from making an informed choice. “Misleading women, whether intentionally or unintentionally, about the benefit of mammography screening is a serious issue. All of those in the business of informing women about screening should recall that medical systems are for patients, not the other way around.”

“We should not be selling screening. We should be giving people the numbers they need to decide for themselves.”

That’s exactly why I wanted to take on this contentious topic “The question of whether screening mammography does more harm than good has the potential to shake up the state of medical knowledge, alter our views of ethical practice, and alter our application of screening principles. The stakes are high in this discourse because women’s lives hang in the balance.

This article was the first in Dr. Greger’s 14-part series on mammograms. He says, “There’s just so much confusion, combined with the corrupting commercial interests of a billion–dollar industry.” Other topics include: (See the article for links to these topics.)

Mammogram Recommendations: Why the Conflicting Guidelines?
Should Women Get Mammograms Starting at Age 40?
Do Mammograms Save Lives?
Consequences of False-Positive Mammogram Results
Do Mammograms Hurt?
Can Mammogram Radiation Cause Breast Cancer?
Understanding the Mammogram Paradox
Overtreatment of Stage 0 Breast Cancer DCIS
Women Deserve to Know the Truth About Mammograms
Breast Cancer and the Five-Year Survival Rate Myth
Why Mammograms Don’t Appear to Save Lives
Why Patients Aren’t Informed About Mammograms
The Pros and Cons of Mammograms