Can Carb Backloading Help You Lose Weight?

There are many diets that claim to help you lose weight and burn more fat. Some work well and other are just fads that might help in the short term but lead to long-term weight gain.

One dietary approach that is becoming increasingly popular is carbohydrate backloading. In this article we’ll break down exactly how it works, and whether or not it’ll help you lose weight.

Here’s what we’ll cover:

• What is carb backloading?
• How does it work?
• Can it help you improve your body composition?

What is Carb Backloading?

A good place to start before we talk about backloading would be to define exactly what carbohydrates are. That way you’ll better understand exactly what the diet is all about.

This food group is made up of starches, sugars and fibers found in foods such as grains, vegetables and fruits. They provide the body with it’s primary fuel source, particularly during higher-intensity exercise. 

They are called carbohydrates as they contain carbon, hydrogen and oxygen. Many sugars have the chemical formula of C6H12O6 – for that reason this food group is sometimes referred to simply as CHO. 

It is not a particularly calorie dense food, providing you with 4kcal per gram – this is much lower than fat, which provides 9kcal per gram. 

It is however relatively easy to overeat – and that can lead to fat gain. When you eat too many calories, your body stores them as fat, ready to use later. Only later never comes.

Carb backloading is a process by which carbs are manipulated so that you avoid them prior to a workout, then include them in your post-workout meal. That way you are less likely to overeat them.

The diet was first proposed by physicist-cum-nutritionist John Kiefer and shares some similarities to other carb-manipulating diets such as IIFYM and intermittent fasting. 

The main ideas are to:

• Keep carb intake to a minimum throughout the day
• Eat a lighter breakfast and lunch and have large carb-based meals after training
• Train in the afternoon or evening to increase the time without carbs
• Start to eat carb foods around 30 minutes prior to training, and throughout the remainder of the day

The Theory of Carb Backloading

Whilst this approach looks like a form of quite simple nutrient timing, the science is slightly more complex.

You are more sensitive to the hormone insulin sensitivity in the morning than at night – in both fat and muscle cells. Insulin is a very anabolic hormone, meaning that in the right environment it can help you build muscle and lose fat.

When you eat carbs, insulin pushes it into either your fat cells orr your muscle cells dependent on environmental factors such as activity, overall energy intake, metabolic rate etc.

Pre-training your fat cells are more receptive to carbs. This means that lots of carbs early on in the day can lead to more fat storage. Fewer carbs therefore means lower fat storage.

When you train in the gym you create muscle damage – this in turn gives signals to your cells to grow back bigger and stronger to stop the damage from happening again. Part of this process is that your brain tells you that you feel hungry, so you eat more food and consequently have more nutrients to feed the muscle.

If you eat your carbs after muscle damage has occurred, nutrients are not sent to fat cells for storage but to the muscles instead. Your body preferentially shuttles nutrients into the muscle cell to help it repair. More nutrients in the muscle means less in the fat cell.

Where this diet might start to bait the interest of bodybuilders, physique athletes or anyone after general fat loss is that carbs don’t have to restricted to ‘healthy’ sources either – you’ve almost got a licence to eat what you want. This includes ice cream. pizzas, cakes or whatever else takes your fancy…

But. You have to make sure that you burn more calories in a day than you take in – a so called calorie deficit. If you eat as many calories as you want, all day and every day, this will eventually lead to weight and fat gain so you can eat what you want, just not as much as you want.

The science sounds brilliant and pretty revolutionary. But do studies of carb manipulation back up the claims? Let’s find out…

Key Point: Carb backloading is a diet where all daily carbs are eaten in the evening after training

What Do The Studies Say?

In the original studies, CHO backloading was found to be an impressive way of losing fat and gaining muscle.

For example, a study from the mid 1990s published in the Journal of Nutrition [1] found that eating most of the daily calories in the evening resulted in more fat loss whilst at the same time having less muscle loss.

The study recruited 10 female participants and asked them to follow a specific diet for two 6-week periods. The ladies were asked to either eat 70% of their daily calories in the morning, or in the evening. This resulted in promising benefits.

Unfortunately, whilst this paper is still often referred to when justifying carb backloading, the number of actual participants in the study was quite small. Additionally, the method in which body fat was assessed was the rather unreliable bio-electrical impedance – a machine notorious for misreadings and inaccurate data.

These two factors combined means that this study is far from reliable.

In 2011, a second study was conducted to further investigate the effect of carb backloading on weight and fat loss [2]. It was specifically designed so that calories were restricted and carbs were eaten mostly at dinner.

Over a period of 6 months, 78 overweight police officers were asked to follow a CHO backloading diet. They had a number of measurements taken from them on a regular basis, including hunger scores, bloods and of course body fat.

The results seemed promising – the group that ate more carbs at dinner lost more weight, improved a number of metabolic markers and felt less hungry.

This study is currently probably the best research to back up carb backloading for weight loss. It’s worth noting though that the group only lost an extra 5 lbs – not exactly a groundbreaking amount.

A deeper look at the methods of the study show that a lot of the diet was self-reported, meaning that there could have been inaccuracies in collection of the data. So whilst the study seems to be a great sales pitch for the diet, it might not be as reliable as it seems.  

Are There Any Studies Showing that carb backloading doesn’t work though?

Like with any new dietary system, more and more independent trials are conducted and more and more research is made available once the diet hits the mainstream.

Initial studies are usually conducted to back up the efficacy of a diet, then shortly after that, more studies come out with strong research methods and more often than not tend to dispel it.

One interesting study published in Nutrition [3] found that regardless of whether daily calories were split into morning, evening or frequently throughout the day, weight loss was the same in all groups – more than likely down to the fact that participantsall received the exact same daily calorie deficit diet. 

Similarly, Sensi et al [4] wanted to assess whether different meal timings would give a different ‘metabolic fate of nutrients’. They asked participants to follow a calorie deficit diet in which they would eat their food in the morning, at 6pm, or equally distributed throughout the day.

The group that ate at 6pm showed higher fat oxidation and a lower CHO oxidation than the other groups, which backs up the original theory of carb backloading – unfortunately though, this didn’t lead to any more weight loss than the other groups.

Key Point: Carb backloading appears to help with weight loss, although it appears this may be down to the calorie deficit and not the meal timings themselves.

Summary

Carb backloading is a dietary practice where carbohydrates are eliminated from the diet until the evening, once exercise training has taken place. You can then eat whatever type of carbohydrates you like, as long as you remain in a deficit.

It works very much on the theory that insulin helps to shuttle carbs into muscle cells post-training as opposed to fat cells, leading to muscle gain and fat loss.

Early research seemed positive but had methodological flaws. As more and more research becomes available there doesn’t seem to be many differences between this approach and a standard calorie restricted approach.

Ultimately, the big question is whether or not carb backloading helps you lose weight, or whether it is the overall diet that puts you in a calorie deficit.

We’d suggest that if this is a diet you would like to try then see how you get on – don’t expect miraculous changes to your weight in comparison to a normal, restricted diet, but if you find it easier to follow than other calorie deficit diets and it works for you then that’s brilliant.