How Many Carbs Should I Eat Today?


image: Love Life Blog

Do you know how many carbs you eat in a day?

Before you answer, here is a brief refresher: All foods are composed of 3 macro-nutrients – protein, fat, and carbohydrates. Their intake is measured in grams. Each gram of protein or carbohydrate is equal to 4 calories. Each gram of fat is equal to 9 calories.

Back to real life: Most people consume about half of their daily calories from carbs. For a 2000 calorie diet, that works to 1000 calories, equal to 250 grams of carbs per day.

Is this good or bad?

The USDA recommends that 45-65% of our daily calorie intake should be from carbs, so half is well within that range. Does this seem counter intuitive to you? Were you expecting a recommendation for a much lower daily carb count?

Before we address this perceived gap, let’s understand what carbs are.

What you need to know:

Carbs are scientifically classified into 4 groups based on the length of their molecule chains:

  1. monosaccharides – is a single molecule. The most famous is glucose, a basic  energy source for cells in our body.
  2. disaccharides – such as table sugar, made of two molecules
  3. oligosaccharides – 3-10 molecules long
  4. polysaccharides – anything longer. These include starches and fibers.

From a nutrition perspective, a much easier way to classify carbs is:

  1. Good carbs
  2. Bad carbs

All carbs eventually break down into glucose for our body to use. The distinction between good and bad carbs is based on how fast the carb turns into glucose and spikes our bloodstream. Those blood glucose spikes are unhealthy. They lead to a brief “sugar high” and then a prolonged low, which increase hunger.

So what are examples of good carbs?

You probably know the answer – good carbs are found in fresh fruit and vegetables, legumes, and whole grains.

And bad carbs?

Bad carbs can be found in soft drinks, white breads, cookies, and most highly processed foods. A can of soda has 40 grams of carbs!

Where does fiber fit into this story?

Dietary fiber is a type of long chain carbohydrate (polysaccharide). When it is present in a food, it takes the body longer to turn that food into glucose. Fiber is found in vegetables, fruits, whole grains, and legumes. It is indigestible. Most Americans consume less than half of the daily recommended fiber.

Why do people go on low carb diets?

When people go on “low carb” diets, they stop eating mostly bad carbs. As a result, they begin to feel better and improve on major markers such as weight, blood glucose, etc… This has spawned an entire industry of fad diets (Atkins, South Beach, etc…)

Keep in mind, our bodies use glucose as an energy source for muscles, the nervous system, and the brain. While muscles can store glucose for future use, the brain need a constant supply in order to function properly. Some is stored in the liver (as glycogen), but without continual replenishment, we run out of glucose within a day or two. In some cases fat or protein can be converted into glucose, but not as effectively as conversion from carbs.

In fact, if the body gets no carbs, it starts to break down fats in order to produce glucose for the brain. While this may sound like a good idea, a side effect is the formation of ketone bodies?

Ketone what???

Ketone bodies are a by-product of fat breakdown, that can cause ketosis – a condition that messes with your body. Ketosis causes headaches, mental slowdown, dizziness and interestingly a fruity acidic breath. A prolonged state of ketosis may cause serious health issues.

OK, I’ll get some carbs, but what if I eat too many?

Excess carbs will be stored as fat in the body.

So how many carbs should I consume per day?

Unfortunately, there is no consensus on this. While the USDA recommends a range of 200-300 grams a day, many nutrition experts think this is too high because typically people will eat mostly refined carbs. That’s why you’ll see recommendations of 125-150 grams of carbohydrate from many pros.

At the end of the day, you’ll need to find what carb proportion works for you. Consult a registered dietitian for more specific advice.

One piece of advice we can provide – learn to read the nutrition label on products and look for products that have a high fiber count. A good rule of thumb is a ration of 6:1 or better – 6 grams of total carb to every 1 gram of fiber. For example, a whole grain bread with 15 grams of carbs and 3 grams of fiber has a 5:1, which is good.

  • Tiffany

    I do best at 100-120 grams per day…all from fruit, veggies, and a little bit of dairy.

  • Christopher

    It’s a bit hard to take someone seriously if they post an article about carbohydrates without mentioning glycemic index.

    You mention good carbs and bad carbs and vaguely relate them to blood sugar levels, but that’s not terribly useful.

    Glycemic index is a measure of how quickly a food product releases glucose into the blood stream. The lower the glycemic index, the longer it takes for the glucose to be released into your blood stream.

    This can be for two basic reasons, physical inaccessibility and chemical inaccessibility.

    In the first case, for sugars to be absorbed by the body, they must first contact the gut wall. If you are eating vegetables, rice, or other carbohydrate sources that are high in fibre, it take longer for the carbohydrate component of the food bolus to actually contact the gut wall. This in turn means that the food will take longer to release the glucose component.

    The second is chemical accessibility, and this is a lesser component of the glycemic index. You’ve probably heard of a complex carbohydrate. This is simply glucose, fructose or otherwise linked in a larger complex molecule, such as starch, that the body must first break down in order to access the glucose component.

    These two reasons are why you see plenty of fat people slurping on soda and eating candy (Glycemic index of 100), but not as many fat people eating basmati rice (glycemic index of ~60) wholemeal bread (55) Bananas (55) and so on and so forth.

    Eating foods with a low glycemic index is a good thing, as the slow release of sugar leaves you satisfied for longer, puts less strain on the glucose handling system of the body (pancreas and glucose receptors of cells) which can help prevent and improve type 2 diabetes, makes it less likely to store the carbohydrates as fat, and stops your glucose levels from rebounding, especially if combined with caffeine intake.

    Be aware of the other components of food however, just because something is a ‘good’ carbohydrate, which as I’ve just explained is a carbohydrate with a low glycemic index, does not mean that it is good for you. Be aware of fat content also, and always keep in mind the total calorific content of the meal you are eating.

    Because I am not promoting any website in general, please google glycemic index if you want a list of foods that would be considered ‘good’ carbohydrates’, if you have any questions please ask them in the reply section below.

    I am a biomedical scientist, and quite happy to answer your questions.

    • Diana

      Can you share your thoughts on agave syrup. Better or worse than sugar, corn syrup, honey, rice syrup etc.

      • Christopher

        Any syrup product is going to be very rapidly absorbed by the body as it is going to be a simple carbohydrate that can easily coat the intestinal wall.

        What will distinguish these products is their perceived sweetness. A sweeter product will allow you to use less.

        • Diana

          Regarding agave syrup…is the higher amount of fructose content compared to table sugar beneficial or detrimental to the body.

          • Christopher

            At moderate levels of consumption, the differences should be negligible. Your body is pretty good at switching fructose to glucose and vice-versa as its metabolism requires.

            The danger of using either is in the fact that it’s a refined carbohydrate, not in whether it contains fructose or sucrose. The problem is the simplicity of the molecule, and the inherent bio-availability which spikes blood sugar rapidly.

            Use them in moderation and you should be fine, both should be considered junk food.

          • Diana

            Thank you for taking the time to answer my questions.

    • Fooducate

      Thanks Christopher, for joining the community and taking the time to discuss the matter in depth. While glycemic index (and more so glycemic load) could be useful, there is simply not enough data to be useful. Of the hundreds of thousands of foods available in grocery stores, only a few thousand have been empirically tested for GI. Often times the same food (say an apple) may have greatly varying GI. Additionally, GI changes once 2 items are consumed together. A potato may have high GI, but eaten together with some butter, its GI drops dramatically. So practically speaking, GI is not an effective tool for most people.

    • caz

      i got great info from the article.. I didn’t read anything claiming this was all inclusive and the end all to carb research.. It certainly is a great begining. Look at your first comment.. what a derelict snob. You here to share info or garner attention for yourself.. you amazing scientist. You could have approached this with a ” i want to share and add to this” approach, but instead you attempt to belittle the author straightaway thus giving away your true nature and intent.

  • Christopher

    Glucose cannot be made from fat. The ketones part is correct. In the absence of sufficient glucose, when the fat breaks down to generate energy it will be diverted into ketones.

    Unless you are referring to the 3-carbon glycerol backbone of the triglyceride (three fatty acids + glycerol). But this probably isn’t a net production of glucose because it was probably a glucose molecule that generated the glycerol backbone to be able to attach the three fatty acids that, combined, made up the triglyceride in the first place.

    The bulk of your message is helpful, but getting something basic like this incorrect can be distracting.

    The carbon backbone of most amino acids from your protein can be used to generate glucose. So it is correct to indicate glucose can be made from protein.

  • Lisa

    I don’t know anyone who eats 200-300 g per day, even if they eat bread. I’ve only seen dieticians pushing something close to that amount, even if they don’t spell it out, because they expect people to shove 11 servings of grains into their bodies daily (whaaat?). Is that 125-150 a new recommendation? I like it.

    • Fooducate

      Carbs come from multiple non-bread sources as well. Fruits, vegetables, pasta, potatoes, rice, etc… That adds up nicely over the course of the day.

      • Lisa

        Yes, a fact I’d like to see more dietician acknowledge! :) If there’s a shift in attitude like I see in this post, it’s welcome.

  • Helen

    i think it’s probably important to say that, if you cut down your carb intake, even moderately by, say, giving up sugar and swapping refined carbs for whole grains, you may well find you experience temporary flu-like symptoms that are a lot like the symptoms of ketosis mentioned above. I know I did: and I didn’t eat a lot of sugar or refined carbs to start with. It turned out that they were just withdrawal symptoms. I think it’s important that people shouldn’t mistake these temporary symptoms for something that will cause them harm, and as a result be dissuaded from making good dietary changes.