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How To Guide – Carb Cycling For Fat Loss

By Chris Spearman

rish born and raised Chris Spearman is a well-known Fitness Model, ex-semi Pro Rugby player, PhD Nutrition Athlete, National Champion Sprinter and Cancer Research PhD Student…
Read more.

We all know that carbohydrates are used as energy by our bodies; they fuel our workouts and provide ample fuel throughout the day as well as replenishing our glucose and glycogen stores to prevent fatigue.

But how can we use carbohydrates to our advantage? How can we get full benefit from carbohydrates and make them our biggest tool rather than our enemy? One way of using carbohydrates to our advantage is to carb cycle.

Healthy Nutrition

What is Carb Cycling?

Carb cycling is really quite simple, it works on the premise of manipulating the amount of carbohydrate in the diet from day to day to help aid fat loss and improve body composition throughout the week.

Carb cycling diets focus on carbohydrate intake due to its primary role in metabolic processes that are related to burning fat and building muscle.

The most important primary goal of a carb cycle is to deplete and refill muscle glycogen stores, help to regulate fat burning and muscle building hormones simultaneously, increase thyroid activity and even support the psychological state of the individual, which can often be over-looked massively.

Carbs Aren't The Enemy

It is well known that high carbohydrate consumption causes the release and stimulation of insulin in the blood, helping to shuttle nutrients into the muscles, replenishing lost muscle glycogen, aid in recovery and stimulate proteins synthesis.

High carb days can also be a great tool for topping up energy levels and prepare your body for intense training days.

On the other hand, low carb days promote fat as a fuel source. During these days, your body will be able to burn through glycogen that is stored from the high carb days eventually dipping into fat stores for energy.


  • Throughout the week, you rotate through high-carb, moderate-carb, and low/no-carb days.
  • All days for me will require roughly the same protein intake generally spaced out through the day.
  • My fat intake is inversely related to my carbohydrate intake. That is, your fat intake is low when your carbs are high, and vice versa so that total calories will be roughly the same.

Exact protocols vary in terms of specific numbers, but all are based on that simple structure.

For example, you may do 4 low-carb days, followed by a high-carb day, and then a no-carb day, and then start over.

Or you may do 3 low-carb days followed by 1 high-carb day, and then back to the low-carb and so on.e.

The Benefits of Carb Cycling

Carb cycling will allow you to eat carbs from clean sources without adding body fat. The cycling element enables you to better utilise fat for burning as fuel, as opposed to burning carbs and muscle tissue for fuel by switching between the insulin pathway and the glucagon pathway more efficiently.

Carbs are not the evil villain the media paint them out to be and should certainly not be omitted from your nutritional program.

Protein Sources

In fact, carbohydrates are the most useful tool when it comes to dieting, manipulating your metabolic rate and allowing yourself or your clients to achieve their goals. Improper use of carbohydrates is what you need to watch and the wrong carbohydrates in the wrong quantities at the wrong time can be stored as fat.

Carbohydrates are not essential to the body, although they do make dieting and eating in general a lot easier and a lot more pleasurable.

This carbohydrate bashing is not helped by those who are jumping on the proverbial bandwagon to make a buck off the latest trend in dieting. There are so many low carb foods hitting the grocery stores daily, everything from low carb bread to low carb potato chips can now be found with a low carb label. Not long ago it was fat bashing and low fat foods.

What will be next? Protein?!

Reaching a Plateau

Carbs Aren't The Enemy

Every now and then, you will more than likely reach a fat burning plateau. This is the perfect time to implement a "tweak" in the carb cycle plan.

The human body is an amazing thing, it will eventually adapt to any stressors placed upon it, therefore, very often you need to keep adjusting your nutrition and training e.g. after time you may stop burning fat as fuel and this additional tweak may be crucial.

When a plateau like this arises I will often if I haven’t already integrate a refeed day/high carb day/cheat meal. A cheat meal simply has to be an excess of calories and a substantial elevation in carbohydrates if we want to spark up a metabolic response and affect the hormones responsible for fat loss.


A cheat meal does not necessarily mean eat rubbish! More often than not it will be far more beneficial to have a clean re-feed. These re-feeds will have an extremely high percentage of carbohydrates in them and generally if I have a high carbohydrate meal then fats are low.

Perfect example would be: 500g white potato and 150g of steak spaced 3-4 times throughout the day generally in and around my workout that day.

Within 24-48 hours post re-feed, your body will turn into a metabolic furnace. You will become visibly leaner as the calories are now being burned at an exponential rate before it begins to ease off. Make the most of this change in metabolism is key, although it may be tough, I make sure to increase cardio in the 48 hours after my re-feed along with a drop in calories (carbohydrates).

Another way you can also accomplish this (although not as enjoyable) is to go to zero carbs for 3 days and 3 days only. This will accomplish the same thing as the 3-4 high carb days or the "cheats." This is the only time to take fibrous vegetables into consideration, as no carbs whatsoever should be ingested during the 3 zero carb days.

I would never stay at zero carbs for any longer than 3 days, and rarely go below 30-40g of carbs for more than a day or two, throughout the entire length of the diet other than this occasional zero carb 3 day period.

Any lower, and you will notice that brain function may suffer; thinking becomes cloudy, as the brain needs a certain amount of carbs to function optimally

Leptin Plays a Massive Role in Carb Cycling

What is leptin? Leptin is a hormone secreted from fat tissue that plays an integral part in the regulation of hunger and feelings of satiety. Like all hormones, leptin has a wide variety of functions, however its primary function and most relevant to us is its role in regulating fat-cell size (1).

The mechanism of action is:

  • Following the release of leptin from fat cells
  • A signal is sent to the brain to reassure the body that adequate food has been received
  • It is now time to put the knife and fork down (2, 3).

For this reason, leptin is extremely important in the regulation of fat loss albeit indirectly. Four key factors that regulate leptin levels include:

Leptin Graph

1. Fasting

Although it seems pretty straight forward, how often do we hear: “I was so busy I had no time to eat” or “I was so busy I didn’t have time for breakfast”? Usually followed by: “I’m so hungry I could eat the house”.

This leaves you in a state of starvation, which causes havoc with your leptin levels. Periods of fasting is thought to activate a survival mechanism that down regulates leptin levels and increases the hormone responsible for feeling hungry: ghrelin (1, 6).

Leptin levels in extreme cases can become clinically suppressed, although it is unclear how long this takes, it is very likely that those with extremely low percentages of body fat consuming extremely low and reduced-calorie-diets are experiencing notable decreases in leptin concentrations.

woman exercising

2. Exercise

We all know that exercise burns calories and overtime this may lead to weight loss and body fat store reductions. However, most of us don’t take into account that overall body mass including fat tissue impacts total daily energy expenditure, believe it or not.

In fact, specific studies have shown significant reductions in basal metabolic rate following fat loss. Therefore, whilst losing weight I fantastic for our physiques, it can have a negative impact on leptin levels AND metabolism (7).

3. Body Composition

As we have mentioned, fat cells secret leptin, therefore the lower our percentage of body-fat is, the less of this appetite-suppressing hormone gets secreted (2, 10, 11). Importantly people with a higher body-fat percentage generally have elevated leptin concentrations, which researchers expect is due to leptin resistance (10, 12, 13).

This insensitivity is caused by the brain becoming insensitive to the hormone itself, and therefore drastically reduces its ability to affect hunger and satiety.

Overfeeding also effects leptin concentration in the body. Although overfeeding does elicit a change in leptin levels, not all macronutrients have the same response.

For example: fat has virtually no effect on leptin concentrations, believe it or not and even reduces leptin levels in some cases (14, 15, 16). Contrary to fats, carbohydrates (as would be expected) have a positive effect on leptin (15, 17, 18).

It is thought that high-glycaemic carbs may be the sole reason for increases in leptin (19). Leptin doesn’t increase immediately after a meal per se, instead the increase in leptin levels are anywhere from 4-48 hours after carbohydrate refeeding (1, 17, 20).

It’s important at note at this point that overdosing on protein doesn’t directly affect leptin levels.

What Carbohydrates to Use

It is really handy to keep a nutrition journal when cycling carbs to be able to chart progress and make adjustments during your nutritional program. This takes the guesswork out of dieting, and can also be looked back upon in the future to see how the body responded to certain tactics, and is an invaluable tool.


It is really handy to keep a nutrition journal when cycling carbs to be able to chart progress and make adjustments during your nutritional program. This takes the guesswork out of dieting, and can also be looked back upon in the future to see how the body responded to certain tactics, and is an invaluable tool.

Some tweaking will of course be necessary for most, as some of us are a bit more "carb sensitive" than others. Activity level, training intensity level, age, as well as sex, will determine how much you will need to adjust things.

Over time you can decide whether you want to raise them a bit, or lower them, based on your results, and your body's feedback. Generally I will get clients of mine to cycle carbs differently and see how their body responds before approaching any show or contest.

It is important to stay vigilant with excess carbohydrates, when eaten in excess or at the wrong times they can add adipose tissue to the body if not integrated efficiently.

The first thing I do when arranging a nutritional program for a client is to have them cut back on junk food until it is completely eliminated from their nutritional program except for the rare treat. Eating junk food is a conditioned act and can be easily eliminated psychologically or replaced with other reward systems.

It is not a mystery, and all that's needed by the person looking to lose body fat is a lifestyle change! Cut down on eating rubbish, and you'll be well on your way to better health, increased energy, and a leaner body.

These are the best sources of clean carbs to use when dieting in general, and when cycling carbs:

Baked Potatoes Sweet Potatoes Brown Rice Oats
click to buy now

Source Of Carbs

utrition Table

It is a silly idea to completely omit any food type out of your diet and this can often lead to an even great intolerance to that food type.

Food allergies are a lot less common and you think and often recently it seems to be in fashion to be “intolerant’ to a certain food. However, I rarely eat bread in my normal diet and dairy products are seldom seen also when dieting.

Are Simple Carbs/Sugars Bad?

NO!! Simple carbs can be really affective when used at the right time. My intra and post workout nutrition is littered with simple carbohydrates.

For example: Intra workout I will use Waxy-Vol by PhD Nutrition or a simple cyclic dextrin with a total carbohydrate intake or 25-50g of carbs and very often 25-50g of carbohydrates from either 2:1 Recovery or cyclic dextrin mixed in with my Pharma Whey HT+.

woman exercising

Finally, don't always be overly concerned with the glycaemic index of the foods, but instead be more concerned with total carbs ingested for the day. It should never be too high!

After all, calories in Vs calories out will paint a bigger picture than your glycaemic index of carbohydrates OR the bioavailability of the protein you consume.

Have you ever tried carb cycling? What were your results like? Share your story with us on Facebook
Jamie Lloyd

About Chris

Irish born and raised Chris Spearman is a well-known Fitness Model, ex-semi Pro Rugby player, PhD Nutrition Athlete, National Champion Sprinter and Cancer Research PhD Student.

Sport has always played a vital role in Chris’ life.  As has science, and it’s this passion for both and how they interact that lets him use his molecular and physiological knowledge to get the very best out of his, and his clients, training programmes.

You can connect with Chris over on Facebook, Twitter or Instagram.

Or read Chris’ Muscle Food interview to find out more!


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