We Really Can Make Glucose From Fatty Acids After All! O Textbook, How Thy Biochemistry Hast Deceived Me!
Biochemistry textbooks generally tell us that we can’t turn fatty acids into glucose. For example, on page 634 of the 2006 and 2008 editions of Biochemistry by Berg, Tymoczko, and Stryer, we find the following: Animals Cannot Convert Fatty Acids to Glucose It is important to note that animals are unable to effect the net synthesis of glucose from fatty acids. Specficially, acetyl CoA cannot be converted into pyruvate or oxaloacetate in animals. In fact this is so important that it should be written in italics and have its own bold heading! But it’s not quite right. Making glucose from fatty acids is low-paying work. It’s not the type of alchemy that would allow us to build imperial palaces out of sugar cubes or offer hourly sweet sacrifices upon the altar of the glorious god of glucose (God forbid!). But it can be done, and it’ll help pay the bills when times are tight. All Aboard the Acetyl CoA! When we’re running primarily on fatty acids, our livers break the bulk of these fatty acids down into two-carbon units called acetate. When acetate hangs out all by its lonesome like it does in a bottle of vinegar, it’s called acetic acid and it gives vinegar its characteristic smell. Our livers aren’t bottles of vinegar, however, and they do things a bit differently. They have a little shuttle called coenzyme A, or “CoA” for short, that carries acetate wherever it needs to go. When the acetate passenger is loaded onto the CoA shuttle, we refer to the whole shebang as acetyl CoA. As acetyl CoA moves its caboose along the biochemical railway, it eventually reaches a crossroads where it has to decide whether to enter the Land of Ketogenesis or traverse the TCA cycle. The Land of Ketogenesis is a quite magical place to which we’ll return in a few moments, but n Continue reading >>
Fatty Acid Metabolism
Fatty acid metabolism consists of catabolic processes that generate energy, and anabolic processes that create biologically important molecules (triglycerides, phospholipids, second messengers, local hormones and ketone bodies). Fatty acids are a family of molecules classified within the lipid macronutrient class. One role of fatty acids in animal metabolism is energy production, captured in the form of adenosine triphosphate (ATP). When compared to other macronutrient classes (carbohydrates and protein), fatty acids yield the most ATP on an energy per gram basis, when they are completely oxidized to CO2 and water by beta oxidation and the citric acid cycle. Fatty acids (mainly in the form of triglycerides) are therefore the foremost storage form of fuel in most animals, and to a lesser extent in plants. In addition, fatty acids are important components of the phospholipids that form the phospholipid bilayers out of which all the membranes of the cell are constructed (the cell wall, and the membranes that enclose all the organelles within the cells, such as the nucleus, the mitochondria, endoplasmic reticulum, and the Golgi apparatus). Fatty acids can also be cleaved, or partially cleaved, from their chemical attachments in the cell membrane to form second messengers within the cell, and local hormones in the immediate vicinity of the cell. The prostaglandins made from arachidonic acid stored in the cell membrane, are probably the most well known group of these local hormones. Fatty acid catabolism A diagrammatic illustration of the process of lipolysis (in a fat cell) induced by high epinephrine and low insulin levels in the blood. Epinephrine binds to a beta-adrenergic receptor in the cell membrane of the adipocyte, which causes cAMP to be generated inside Continue reading >>
How Long Does It Take For Sugar To Become Fat In Our Body?
Every carb is digested into glucose. Yes, in the end, the candy bar turns into glucose just like the cup of peas. Sure, the candy bar turns into glucose faster, but thats the only difference. The candy bar has a bunch of monosaccharides that are quickly metabolized whereas the peas have a bunch of oligosaccharides that take longer. The sucrose found in a pineapple is no different chemically than the sucrose in our favorite type of dessert. And high-fructose corn syrup is chemically similar to sucrose. What is especially fattening, then? Overeating. That is, feeding your body more energy than it needs every day, regardless of what foods are providing the excess energy. This study ( ), conducted by researchers at the University of Hawaii, is an extensive review of sugar-related literature. Heres a quote from the paper: It is important to state at the outset that there is no direct connection between added sugars intake and obesity unless excessive consumption of sugar-containing beverages and foods leads to energy imbalance and the resultant weight gain. Overconsumption and energy imbalance are the keys here. The more carbohydrates you eat, the more energy (calories) you put into your body. The more energy you give your body, the more energy you have to burn to prevent fat storage. You see, if you give your body a lot more energy than it needs every day, whether from excess amounts of protein, carbohydrate, or dietary fat, youll get fatter. This has been conclusively proven in clinical research. There is no debating this fact. And this is where we get to the actual problem with sugar intake and getting/staying fat: the more you eat foods with added sugars, the easier it is to overeat. This is especially true of liquid carbohydrates, including beverages with added sugar. Continue reading >>
Converting Carbohydrates To Triglycerides
Consumers are inundated with diet solutions on a daily basis. High protein, low fat, non-impact carbohydrates, and other marketing “adjectives” are abundant within food manufacturing advertising. Of all the food descriptors, the most common ones individuals look for are “fat free” or “low fat”. Food and snack companies have found the low fat food market to be financially lucrative. The tie between fat intake, weight gain, and health risks has been well documented. The dietary guidelines suggest to keep fat intake to no more than 30% of the total diet and to consume foods low in saturated and trans fatty acids. But, this does not mean that we can consume as much fat free food as we want: “Fat free does not mean calorie free.” In many cases the foods that are low in fat have a large amount of carbohydrates. Carbohydrate intake, like any nutrient, can lead to adverse affects when over consumed. Carbohydrates are a necessary macronutrient, vital for maintenance of the nervous system and energy for physical activity. However, if consumed in amounts greater than 55% to 65% of total caloric intake as recommended by the American Heart Association can cause an increase in health risks. According to the World Health Organization the Upper Limit for carbohydrates for average people is 60% of the total dietary intake. Carbohydrates are formed in plants where carbons are bonded with oxygen and hydrogen to form chains of varying complexity. The complexity of the chains ultimately determines the carbohydrate classification and how they will digest and be absorbed in the body. Mono-and disaccharides are classified as simple carbohydrates, whereas polysaccharides (starch and fiber) are classified as complex. All carbohydrates are broken down into monosaccharides before b Continue reading >>
When Does Glucose Convert To Fat?
Despite the fact that eating a jelly doughnut seems to deposit fat directly on your hips, converting sugar to fat is actually a relatively complex chemical process. Sugar conversion to fat storage depends not only upon the type of foods you eat, but how much energy your body needs at the time you eat it. Video of the Day Your body converts excess dietary glucose into fat through the process of fatty acid synthesis. Fatty acids are required in order for your body to function properly, playing particularly important roles in proper brain functioning. There are two kinds of fatty acids; essential fatty acids and nonessential fatty acids. Essential fatty acids refer to fatty acids you must eat from your diet, as your body cannot make them. Nonessential fatty acids are made through the process of fatty acid synthesis. Fatty Acid Synthesis Fatty acids are long organic compounds having an acid group at one end and a methyl group at the other end. The location of their first double bond dictates whether they are in the omega 3, 6, or 9 fatty acid family. Fatty acid synthesis takes place in the cytoplasm of cells and requires some energy input. In other words, your body actually has to expend some energy in order to store fat. Glucose is a six-carbon sugar molecule. Your body first converts this molecule into two three-carbon pyruvate molecules through the process of glycolysis and then into acetyl CoA. When your body requires immediate energy, acetyl CoA enters the Citric Acid Cycle creating energy molecules in the form of ATP. When glucose intake exceeds your body's energy needs--for example, you eat an ice-cream sundae and then go relax on the sofa for five hours--your body has no need to create more energy molecules. Therefore, acetyl CoA begins the process of fatty acid syn Continue reading >>
Modern Diet Myth No. 4: Fructose Turns To Fat
Modern Diet Myth No. 4: Fructose turns to fat Fructose the dietary villain de jour is currently giving rise to more myths than anything else and they all seem to relate to fat. Fructose supposedly leads to fatty liver and too much fat in the blood. To top it off, fructose is said to be uniquely fattening! Where do we start? Most of the carbohydrate we eat ends up in the bloodstream as either glucose or fructose. The myth goes that glucose is the good sugar as it is used to power the brain, the muscles and most of the cells in the body. And the fructose is the bad sugar which is quickly taken up by the liver and turned into fat, giving rise to fatty liver. Unfortunately for the myth-makers, no reputable health authority in the world agrees. Fatty liver is certainly a common problem but the experts see it as part of the metabolic syndrome a cluster of abnormalities linked to central obesity and insulin resistance, where the cells of the body become less sensitive to insulin. There is no recommended diet for fatty liver. Instead, health authorities encourage people with fatty liver to lose some weight and increase their physical activity, both of which improve insulin resistance. Our liver certainly has the ability to turn both glucose and fructose into fat its the perfect way to turn any excess carbohydrate calories into a form that can be stored for later use. And sooner or later this fat appears in the blood as triglycerides. However, the idea that all the fructose we eat turns to fat pushing up the level of triglycerides in the blood is just plain wrong. If you are a healthy, normal weight person eating enough food to maintain your body weight your liver only turns a tiny fraction of fructose into fat , about 1-3%. Most of the fructose taken up by the liver is actuall Continue reading >>
How Sugar, Not Fat, Raises Your Cholesterol
Excess carbohydrates and sugar lead to cholesterol and weight gain, explains Dr. Doni Wilson, which is why balancing blood sugar levels every day is so important. When you go to the doctor and get a cholesterol reading, you may be cautioned against eating high-fat foods. But very little fat from foods becomes cholesterol in your blood. What produces cholesterol is rather the excessive consumption of carbs at any one time. The cholesterol and triglycerides in your bloodstream come not from consuming excess fat, but rather, from consuming excess glucose. I’m not just talking about excess glucose over the course of a week or even a day. I’m talking about what happens when you consume excess glucose in one sitting. Let’s take a closer look at exactly happens when your body gets too many carbs at one particular meal. First, you digest the carb-containing food, breaking it down into the individual glucose molecules that are small enough to cross the cells of your intestinal walls and enter your bloodstream. Because you have eaten too many carbs, you have far too much glucose stuck in your blood. You don’t have enough insulin to move all that glucose into your cells. So what happens to that excess glucose? Some of it is stored in your liver as a substance known as glycogen, to be released when you don’t eat. Harking back to our hunter-gatherer days, our bodies created a backup system to ensure that even if we can’t get any food for a couple of days, we won’t starve to death. The liver can only hold so much glycogen, however. So what about the glucose that doesn’t fit? Your body has three choices: convert the glucose into body fat, which translates into weight gain, most likely around your middle; convert the glucose into lipids (fats), which remain in your bloo Continue reading >>
Conversion Of Carbohydrate To Fat In Adipose Tissue: An Energy-yielding And,therefore, Self-limiting Process.
Conversion of carbohydrate to fat in adipose tissue: an energy-yielding and,therefore, self-limiting process. A theoretical analysis of the energy metabolism associated with the conversion ofglucose to fat is presented. In tissues where the pentose cycle furnishes some ofthe NADPH required for fatty acid synthesis, this conversion is an ATP-yieldingprocess. In rat adipose tissue the maximal rate of glucose conversion to fat can be quantatively predicted on the basis of the tissue's ability to use the ATPwhich is generated in excess during this conversion. The energy-generating natureof this process provides the means for a type of regulation which depends onmetabolic state and which, during fasting, contributes to the sparing ofcarbohydrate. Impairment of lipogenesis in the fasting state is attributed to adecrease in the activity of the malate cycle and to the presence of free fattyacids. However, rather than by inhibiting specific enzymes, it is by virtue oftheir quality as substrates for energy production that free fatty acids and theirCoA derivatives appear to inhibit de novo lipogenesis. The regulatory phenomenadiscussed here may explain the failure of the attempts made to identify therate-limiting step for de novo lipogenesis in adipose tissue. Continue reading >>
How Sugar Makes You Fat
Look at how many grams of sugar are in what you’re eating (on the nutritional label). Now divide that number by 4. That’s how many teaspoons of pure sugar you’re consuming. Kinda scary, huh? Sugar makes you fat and fatfree food isn’t really free of fat. I’ve said it before in multiple articles, but occasionally, I’ve had someone lean over my desk and say “How in the heck does sugar make you fat if there’s no fat in it?”. This article will answer that puzzler, and provide you with some helpful suggestions to achieve not only weight loss success, but improved body health. First, let’s make some qualifications. Sugar isn’t inherently evil. Your body uses sugar to survive, and burns sugar to provide you with the energy necessary for life. Many truly healthy foods are actually broken down to sugar in the body – through the conversion of long and complex sugars called polysaccharides into short and simple sugars called monosaccharides, such as glucose. In additions to the breakdown products of fat and protein, glucose is a great energy source for your body. However, there are two ways that sugar can sabotage your body and cause fat storage. Excess glucose is the first problem, and it involves a very simple concept. Anytime you have filled your body with more fuel than it actually needs (and this is very easy to do when eating foods with high sugar content), your liver’s sugar storage capacity is exceeded. When the liver is maximally full, the excess sugar is converted by the liver into fatty acids (that’s right – fat!) and returned to the bloodstream, where is taken throughout your body and stored (that’s right – as fat!) wherever you tend to store adipose fat cells, including, but not limited to, the popular regions of the stomach, hips, but Continue reading >>
Does Carbohydrate Become Body Fat?
Dear Reader, Ah, poor carbohydrates, maligned by diets such as Atkins’ and the ketogenic diet. However, carbohydrates are your body’s main source of energy — in fact your muscles and brain cells prefer carbs more than other sources of energy (triglycerides and fat, for example). To answer your question: research completed over the last several decades suggests that if you are eating a diet that is appropriate for your levels of daily activity, little to no carbohydrate is converted to fat in your body. For most people (unless you have a metabolic disorder) when you eat carbs they are digested, broken down to glucose, and then transported to all the cells in your body. They are then metabolized and used to support cellular processes. If you’re active and eating appropriately for your activity level, most of the carbs you consume are more or less burned immediately. There are two caveats here: first, if you’re eating a lot more calories per day than you are burning, then yes, your liver will convert excess calories from carbohydrate into fats; second, not all carbs are created equal. If you consume too many calories from simple sugars like sucrose and fructose (think sugary sodas sweetened by sugar and high fructose corn syrup) then your body will more readily take some of those sugars and turn them into triglycerides (fat) in your liver. What happens to excess calories that come from carbs? The answer depends on several things: what kind of carbs you consumed, your genetics, as well as how many extra calories we’re talking about. For those who eat a well-balanced diet and have no metabolic disorders, excess dietary carbohydrates are converted by the liver into complex chains of glucose called glycogen. Glycogen is stored in liver and muscle cells and is a sec Continue reading >>
How Does Fat Get Converted To Calories?
Opinions expressed by Forbes Contributors are their own. Answer by Bart Loews , passionate exercise enthusiast, on Quora : How is fat being converted into calories at cellular level? First lets get some term clarification: A calorie is a measure of energy, specifically heat. Its a measurement of an indirect use of your biological fuels. Your body doesnt really convert things to calories, it converts them to ATP which is used as energy. Calories are, sadly, the best way we have to measure this process.Ill assume that the point of this question is: How does fat turn into energy? Fat is a term used interchangeably with lipids and with adipose tissue. Lipids are molecules that consist of a hydrophobic tail with a hydrophilic head. Because of this polarized set up, they are able to cluster together to form barriers between water and non water, like bubbles. Your cell membranes are composed of lipids. Adipose tissue is what makes you fat. Adipose tissue stores lipids in the form of triglycerides or 3 fatty acid chains with a glycerol backbone. These triglycerides are what is broken down to be used for energy. Adipose tissue is made up of collections of adipocytes or fat cells. Adipose tissue is used for insulation, cushioning, and energy storage. You get a particular number of fat cells (between 30 and 300 billion) during adolescence and childhood. You don't lose them naturally, but you can gain more if they grow more than 4 fold from their original size. They grow and shrink as they take on more energy. Fat cells have a few other roles in the endocrine system, they release the hormone, Leptin when they receive energy from insulin. Leptin signals to your body that you're full. The more fat cells you have, the more leptin is released. It's been found that obese people are lep Continue reading >>
Do Our Bodies Convert All Food (fats, Carbs And Proteins) To Glucose, Or In Other Words, Do Our Cells Burn Anything Other Than Glucose?
Answered May 12, 2015 Author has 219 answers and 550.2k answer views Our body doesn't convert all the carbs, proteins and fat we eat to glucose! Carbohydrates: Only those carbohydrates which are digestible by our gut are used, remaining else (cellulose for that matter) remains in the gut, absorbs water and aids in proper digestion; the so called roughage. Yeah, the digested ones which may either give glucose, fructose or galactose as the final product, are all converted to glucose. Proteins: All amino acids obtained from the protein digestion are not converted to glucose, only a few of them are, remaining is converted to ketone bodies (another energy suppplier as glucose). Fats: Fats (neutral fats or triglycerides) are broken down into fatty acids and glycerol. From this, only glycerol and odd chain fatty acid (cf. even chain fatty acid) can produce glucose. So, what's with this compulsion of glucose to be present in the blood in the right quantity always? "Lest the brain will be starved, for it needs glucose from blood", you would have heard. Partly true because brain can live by utilizing ketone bodies as well. But for an optimal neurotransmitter (chemical signals aiding communication between two or more neurons) production Krebs cycle/ citric acid cycle should occur, which would be shunted when brain cells use ketone bodies, in contrary glucose would aid positively for krebs cycle to occur and produce intermediates which can be furthur be utilised for neurotransmitters production. Nevertheless, there are cells solely dependent on blood glucose for survival (RBCs eg), and these cells need to continuous supply of glucose for their survival. Continue reading >>
The Conversion Of Carbohydrates To Triglycerides
Eating a diet high in simple carbohydrates can raise your level of triglycerides—fats carried in the blood and stored in fat cells. The body turns carbohydrates into glucose to use for fuel, but will store excess glucose as fat. High levels of triglycerides can increase your risk for heart disease. Triglycerides are fats. You eat triglycerides in the form of foods such as butters and oil, but your body also makes triglycerides from excess calories, especially from alcohol or from the simple carbohydrates found in sugar-rich foods. Triglycerides help transport cholesterol, which is essential for brain and nerve function, to your cells. Trigylcerides also carry glucose, or blood sugar, to your fat cells. Carbohydrates in the Diet Dietary carbohydrates fall into two categories: simple carbohydrates, or sugars, and complex carbohydrates, or starch and fiber. Most of the simple carbohydrates in the American diet come from sugar, or sucrose, and high-fructose corn syrup, used to sweeten a wide variety of foods. Fruit juices also contribute simple sugars. Whole fruit contains simple sugars, but also contains fiber, which helps slow down the digestion of glucose. All carbohydrates supply the body with glucose, which is used for immediate energy needs and stored as glycogen in the liver and muscle cells. Eating too many simple carbohydrates is harmful, according to the Cleveland Clinic. How Carbs Turn into Fat Your body digests simple sugars and refined carbohydrates such as white rice and white flour rapidly, causing a spike in blood glucose. This causes the pancreas to release more insulin. When your body has more glucose than it needs for energy and has reached its storage capacity for glycogen, the increased insulin prompts the liver to convert glucose into triglycerides, Continue reading >>
How Are Carbohydrates Converted Into Fat Deposits?
How are carbohydrates converted into fat deposits? There are two ways that carbohydrates and body fat interact. One is directly by turning into body fat, and the other is via insulin. Turning into body fat is like adding fat into the fat cells, whereas carbohydrates spiking insulin does not add anything to fat cells per se, but hinders the release. The former is like a + equation, where the latter is a double negative which results in something that seems positive. There is a process called de novo lipogenesis (literally: Creation of fat from non-fat sources) that can occur in the body. This process turns glucose into lipids, which are then stored as body fat. This process is normally quite inefficient in the body  , which suggests that carbohydrates cannot be stored as fat to a high degree. The process can be upregulated (enhanced) if dietary fat comprised almost none of the diet (lesser than 10%, as a rough estimate), if carbohydrate intake is excessively high for a period of a few days, or if one follows an obesogenic diet (diet that is likely to make you fat) for a prolonged period of time.    Carbohydrates spike insulin , which is a hormone that mediates glucose metabolism. Insulin is not good or bad, insulin is insulin. It can be thought of as a lever that switches the body from fat burning mode into carbohydrate burning mode. This allows carbohydrates (and glycogen) to be burnt at a greater rate, but directly reduces the ability of fat to be lost. Overall metabolic rate (calories burnt over the course of a day) does not change significantly, just where the calories come from. When insulin is spiked in presence of ingested dietary fat, the dietary fat can go into body fat stores and not be released since glucose from glycogen is being used in place of Continue reading >>
Can Fats Be Turned Into Glycogen For Muscle?
The amount of fat in the average diet and the amount of stored fat in the average body make the notion of converting that fat into usable energy appealing. Glycogen, a form of energy stored in muscles for quick use, is what the body draws on first to perform movements, and higher glycogen levels result in higher usable energy. It is not possible for fats to be converted directly into glycogen because they are not made up glucose, but it is possible for fats to be indirectly broken down into glucose, which can be used to create glycogen. Relationship Between Fats and Glycogen Fats are a nutrient found in food and a compound used for long-term energy storage in the body, while glycogen is a chain of glucose molecules created by the body from glucose for short-term energy storage and utilization. Dietary fats are used for a number of functions in the body, including maintaining cell membranes, but they are not used primarily as a source of fast energy. Instead, for energy the body relies mostly on carbohydrates, which are converted into glucose that is then used to form glycogen. Turning Fats Into Glucose Excess glucose in the body is converted into stored fat under certain conditions, so it seems logical that glucose could be derived from fats. This process is called gluconeogenesis, and there are multiple pathways the body can use to achieve this conversion. Gluconeogenesis generally occurs only when the body cannot produce sufficient glucose from carbohydrates, such as during starvation or on a low-carbohydrate diet. This is less efficient than producing glucose through the metabolizing of carbohydrates, but it is possible under the right conditions. Turning Glucose Into Glycogen Once glucose has been obtained from fats, your body easily converts it into glycogen. In gl Continue reading >>