Do You Know Your Personal Carb Threshold?

The most common question I get asked as a nutrition coach is about carbohydrates. What carb target should I aim for?

  • How much is too much?
  • Do carbs make you fat?
  • Do you have to cut carbs out completely?
  • Can I eat fruit?
  • Do I have to eat only low GI foods?
  • Why do I lose so much weight when I cut carbs, but gain weight on the scale when I add them back?

Ahhh… why do carbs have to be so confusing?!?!

Let’s spend this post figuring carbs out once and for all!


Although it may be hard to believe, carbohydrates are actually good for you. They supply energy for the body, function our brain, regulate blood sugar levels, improve speed and stamina, recovery, and muscle gain. They even help lower cholesterol and regulate blood pressure (many of these effects are benefits of dietary fiber, which come from carbs). Carbohydrates are our primary fuel.

Cutting carbs completely out of your diet is not healthy and although you may lose faster weight in the short term (much of that will be water weight), it could come with negative health consequences and rebound weight gain.

Other health problems you can get from overly reducing carbs include a slower metabolism, muscle loss, vitamin or mineral deficiencies, bone loss, headaches, difficulty concentrating, bad breath and more.

The goal is the find the highest number of carbs which still give you and edge with fat loss, but also continue to help you to feel good, think clearly, control cravings and give you energy for your daily activities. I call this number your “personal carb threshold.”

This target carb number may vary depending on how much activity you do. You may need more carbs if you do a lot of activity or are an endurance athlete. You may need to lower carbs if you are sensitive to carbohydrates and/or are diabetic.


Can you eat too many carbs? The short answer is, “yes,” but we must dig further for the reasons why. First, eating any food in excess of your daily caloric allotment will result in body fat gain – whether it’s protein, fats, carbs, even vegetables. Eating over your maintenance level calories is the main cause of fat gain. Eat fewer calories than you burn each day and you will lose body fat – period! As Americans, we typically eat too many calories – and most of those calories tend to come from processed carbs and sugars.

However, with that said, you can get an additional edge in fat loss by reducing your carb ratio and balancing your carbohydrates with enough lean protein and healthy fats. I have found this target carb number (personal carb threshold) to be individual for everyone.

The good news is you can find your own target carb number with just a little investigative work.


Your personal carb threshold is the number of carbs YOU should have per day so they are low enough to aid fat loss, but not too low that you have low energy, high cravings, lots of hunger or any negative consequences of too little carbs.

4 steps to find your target number:

1) Food Journal.

Open a My Fitness Pal account (or keep a food journal or use another nutrition tracking app) to measure and track foods for a few weeks to see how your body responds to the carb grams you are eating.

While some people don’t like food journaling or feel it’s too much work (trust me, I used to feel this way too until I saw it’s value!), you don’t have to do it forever and unless you see what you are consuming in black and white, it’s hard to figure out how many carbs are right for you.

NOTE: Simply slashing and removing all carbs completely from your diet without a plan (or forcing yourself to follow someone else’s meal plan or diet) may not be healthy or best for your specific metabolism and carb threshold. I did this myself during the height of my yo-yo dieting years and I understand the temptation to do this, especially when the idea of reducing carbs is new and you don’t know where to start. Instead, start to become your own health detective by food journaling and tracking how you feel on the carbs you eat. Your body will thank you and you will lose more body fat in the long run because your program will be built for YOU.

2) Make sure calories are in line for fat loss first (most important).

You can use an online calorie calculator or My Fitness Pal if you don’t know how to figure this. While online calorie calculators are not perfect – it will at least get you close to target and you can adjust calories from there based on progress. Then start to reduce total carbs each day (increase lean proteins and healthy fats). My Fitness Pal starts by giving you an allowance of around 50% carbs. If you are not losing on that, try reducing to 40% carbs (increase protein to make up the difference). You can set your nutrition targets under “goals” in My Fitness Pal.

3) Start to reduce your sugars, as most of the problem with excess carbs actually comes in the form of processed sugars.

Replacing those foods with whole-grain carbs, fruit and veggies can do wonders.

4) Experiment with your carb numbers and give it a few weeks.


Begin by adding carbohydrates around your workouts. Do this for a few days and then try adding a small serving of carbs to breakfast. Begin with 1/4 to 1/2 cup of whole-grain carbs or fruit and see how you do. Pair this with lean protein and veggies or healthy fats. Then begin adding carbs to lunch. It’s always best to place carbs around the times of day you need the most energy, however it’s a myth eating carbs at night cause weight gain – so you can place them in the evening if you need to.


You will start to lose inches (your pants will be looser), you will have improved energy, you can think clearly and you will lose weight on the scale. Note: weight loss on the scale occurs OVER TIME and may not be in a linear manner week-to-week, as water and hormonal fluctuations influence the scale too – even if fat loss is on the right track.


Your carb number may be too low if you have severe hunger, very low energy, fatigue and/or cravings that begin to get out of control. You want your target carb number to be sustainable so you feel like you can follow your plan even 10 years from now.

It’s important to note you may see a slight increase of weight on the scale when first adding back carbs if you removed them from your diet, but don’t let that stop you. Carbs hold onto water, so when you add them back it is likely the weight gain you see is not fat gain, but water weight (just like we lose water weight when we severely cut carbs). This evens out over time.

Instead monitor circumference measurements and how your clothes feel.


If you are diabetic and your doctor gave you a carbohydrate target you should try to meet each day, be sure to check with them before changing the treatment plan he/she may have you on.

If you are able to test numbers, realize your ratios may need to be lower than the typical American diet (carbs do increase in blood sugar), so perhaps start at 40% carbs and reduce from there. Unless your blood sugar numbers are extremely high or your diabetes are really out of control, you still may not need to severely reduce them from your diet. In fact, having carbs spread throughout the day (paired with protein) can still lower your blood sugar. Again, check your blood sugar and test what works for you. Everyone has an individual carb number – and if you have diabetes finding your unique number is even more important.


Can I eat fruit?

Yes! Figure fruit into your total carb number. And don’t be afraid to eat fruits many people stay away from – like bananas or grapes. Pair those with protein to help keep blood sugar levels steady, especially if this is a concern for you.

Do I have to eat only low GI foods?

Low GI foods are great and help regulate blood sugar levels, but don’t be afraid to add foods some people ban – like regular potatoes. Again, pair with protein and reduce portion sizes.

The most important thing to remember when looking for your personal carb threshold is to be patient and don’t be afraid to experiment. Remember, we always want our forever fat-loss lifestyle to be something we feel is sustainable enough so we can easily be working the same plan 10 years from now.

Keep troubleshooting and testing the numbers. For me, I feel my best and keep my body fat in check by having around 160 grams of carbs per day (40% of my diet from carbs). When I was actively trying to lose body fat I reduced it slightly, but found I didn’t feel good going below 130 grams per day.

I promise you can find the right amount of carbs for you too!