The Nutracheck nutrient guide to: carbohydrates

We place a lot of emphasis on the number of calories in our diets as this is central to our weight loss success, however we mustn't overlook the importance of the nutrients we need too. After all, the food on our plates is made up of different nutrients in varying proportions – calories are just the total energy they all provide.

To help you understand a little more about the nutrients in your food and why they're so important, we're putting together the ultimate series of nutrient guides to bust the myths and equip you with all the nutritional know-how you need to make informed choices about your diet and your health. First up is...carbohydrates!

The basics

Carbohydrates (commonly shortened to ‘carbs’) are a macronutrient found in most foods in our diets. The body uses carbohydrates as its primary source of energy, providing all our cells with the fuel they need to function and keep us alive and well. There are three main types of carbohydrates in our diets – sugars, starch and fibre – and each one is digested, absorbed and used by our bodies in different ways.

• Sugars. Sugars are a type of simple carbohydrate, meaning they’re made up of small molecules. Glucose, the molecule our bodies convert all our food into for energy, is a type of sugar. When we eat sugars, they’re digested by the body quickly, causing a rapid increase in blood glucose – good for a quick burst of energy.
• Starch. Starch is classed as a complex carbohydrate. It’s a much larger molecule, made up of lots of sugar molecules attached in a chain. As a result, starch is a slower energy release carb. It takes longer for the body to break it down, causing a steadier rise in blood glucose and a more gradual, sustained release of energy.
• Fibre. Like starch, fibre is made up of large molecules. However, unlike starch, our bodies cannot properly digest fibre. Although we don’t use these as much for energy, fibre has lots of other important functions within the body, helping to aid digestion and promote gut health.

Do carbs cause weight gain?

In terms of weight loss, the most important factor is ensuring your calorie intake is lower than the calories burned by your body (known as a calorie deficit). Providing you are in a calorie deficit, the nutrients you choose to consume play less of a role.

Many people believe carbs cause weight gain, so their first instinct when losing weight is to cut carbs from their diet. However, much of this school of thought has been fostered by the 'demonisation' of carbohydrates by some sectors of the media and health & wellness industry. In truth, carbs are an important part of a balanced diet. They are the body's primary source of fuel, and many carb-rich foods also provide us with essential B vitamins.

It's all about choosing the right type of carbs:

Refined carbs

When we refer to refined starchy carbs, we mean highly processed carb-rich foods, mainly the ones with a 'white' appearance. This includes white bread, white pasta, white rice, certain breakfast cereals and pastries. During processing, the grains used to make these 'white' carbs are milled and the nutritious, fibre-rich bits are removed. While this might be more visually appealing, it also means that white bread, white pasta, white rice, white flour and processed breakfast cereals are much lower in fibre, so they're digested quicker.

As the starch is broken down into small sugar molecules, it enters the bloodstream and causes a spike in blood glucose levels. Our bodies' tissues are met with a quick surplus of energy and we can feel energetic for a short while after eating. However, elevated blood glucose levels prompt the rapid release of insulin, whose job it is to remove glucose from the blood and move it into 'storage'. This happens at an equally rapid rate, causing a blood sugar crash to match the earlier spike. Therefore, the 'energy' we get from refined carbs is rather short-lived, and only makes us feel more tired and hungry in the long run.

Whole carbohydrates

Now, let's cut back on the highly processed stuff and opt for whole, minimally processed carbohydrates instead – the kind found in whole grains, legumes, nuts and seeds. These carbohydrates have retained all their fibre and nutrients, and take much longer to be digested and absorbed. The resulting increase in blood glucose is more gradual, meaning we don't experience the same 'spike' and 'crash'. Our tissues receive a steady supply of glucose over the course of several hours after we eat, so we can maintain a higher level of energy for longer until our next meal. Plus, the fibre found in these foods helps us to feel fuller for longer, keeping cravings at bay. Minimally processed whole grains are also packed with micronutrients like B vitamins that play a role in energy metabolism.

So, to summarise, the healthiest way to eat your carbs is:

• Trying to ensure the vast majority of your carbs are whole, minimally processed versions, like wholegrain bread, brown rice, wholewheat pasta, oats and barley.
• Moderating your intake of refined carbohydrates, like white bread, cakes, pastries, sugary breakfast cereals and confectionery.

What about sugar?

Like carbohydrates in general, eating sugar itself isn't going to cause weight gain. However, when we eat an excess of sugar, this can contribute extra calories to the diet providing little nutritional benefit – which can result in weight gain. In addition, the way our bodies process different sugars might also have a knock-on effect on how likely we are to overeat:

Free sugars

Glucose is the primary molecule our bodies use to make energy. It's our brain's preferred source of energy, and studies have long identified the effect that glucose has in triggering the pleasure centres of our brain. From birth, our taste buds are primed to prefer the sweet flavour of milk, and as we get older, the modern Western diet is loaded with sugars and sweeteners in the majority of processed foods that perpetuate our cravings for sugar.

Like refined carbs, sugars that are added to foods, as well as natural sugars in honey, syrups, fruit juices and smoothies, are digested easily and quickly absorbed into the bloodstream – even quicker than refined starchy carbs! This causes a rapid spike in blood sugar levels, and a subsequent insulin spike to help bring sugar levels back down. This is what can sometimes result in a blood sugar crash later in the day, resulting in an energy dip and cravings for more sugar. We're more likely to reach for an extra snack or two to keep us going through the day, and this snack is also more likely to be loaded with even more free sugar!

Fruit and veg sugars

These naturally occur in whole fruits and vegetables. As the sugars are contained within the cell walls of the fruit, our bodies take a bit longer to break them down, resulting in a steadier release of sugar into the bloodstream. Fruits and veggies are also packed with fibre, vitamins and minerals, which are important for our bodies to function at their best. As long as your diet remains balanced on the whole, and you're still managing to include sources of protein and healthy fats, your fruit intake shouldn't be of concern. If anything, it's great to include lots of whole unprocessed produce in your diet!

How many carbs should I be eating?

For health, the UK government recommends that around 50% of dietary energy comes from carbohydrates. For a 2000-calorie diet, this would be around 250g of carbs per day. For someone on a reduced daily intake of 1400 calories, this would be 175g per day, although this number will vary depending on your calorie target. In line with these recommendations, our Well Balanced nutrient goal will automatically set your carbohydrate target to 50% of your calorie intake.

The lowdown on low-carb diets

Even though we don't advocate cutting out any food groups, we understand some people find weight loss easier when consuming a lower-carb diet. So if you're going to try it out, it's important to do it the right way!

Traditional lower-carb diet approaches require a reduction in total carbohydrate intake, which is usually counterbalanced with an increased protein intake. Although there are no official guidelines on what constitutes a low-carb diet, a carb intake of 30% of your total daily calories or less can be considered a low-carb diet.

In recent years, other more extreme forms of low-carb diets have become popular, the most famous being the 'keto' diet. What sets 'keto' apart from 'low carb' is that it is high fat and moderate protein – whereas traditional low carb diets tend to be higher in protein. We must also reach 'ketosis' for us to be on a true 'keto' diet.

Ketosis is a state within the body when we start to use fat and protein to make energy instead of glucose. Ketone bodies (or ketones) are produced from fatty acids in the liver when glucose levels are very low. They are then used to produce energy and become the primary source of fuel for the brain – since the brain cannot use fat or protein for this.

Did you know that the keto diet was actually originally devised as a method of treating and managing symptoms of epilepsy?! If your goal is to lose weight and to keep it off, it may be an unnecessary challenge to take on a keto approach, when a more flexible approach could work just as well – and potentially better in the long term. The long-term evidence to support the safety of keto diets is lacking. Indeed, we see that most people who follow this approach tend to do so temporarily, so the sustainability is certainly questionable. The effects of repeatedly removing carbs and then reintroducing them might take a toll on our health if not managed correctly too, so this is another consideration when thinking about the long-term impacts. For these reasons, adhering to a keto diet for weight loss or health isn't something we would recommend at Nutracheck. Instead, following a more balanced approach with only a moderate reduction in carbs is far more likely to be sustainable long term, and doesn't change your body chemistry drastically in the process!

To read more, check out our nutritionist Emma's take on keto: A nutritionist's review of the keto diet

Should I eat a low-carb diet?

Despite the surge in popularity, it's important for you to think about whether a low-carb diet is right for you and your lifestyle. If you find that it helps you to stick to your calorie deficit, that's great! If you feel too restricted and unhappy when carbs are taken off the menu, then remember it's absolutely not necessary to cut down on them!

Some groups of people who have difficulty regulating their blood glucose, such as individuals with diabetes and PCOS for example, might find a lower-carb diet helps to avoid blood sugar spikes and makes managing their condition easier. However, this is again down to the individual – there aren't any official dietary recommendations for these groups of people. Unless advised otherwise by a doctor or healthcare professional, people with diabetes and other conditions can still include carbohydrates in their diets just like everyone else! However, opting for high-fibre carbs and minimising free sugars is still strongly recommended, and especially important for keeping blood glucose under control.

If you're interested in trying a lower-carb diet, the Nutracheck app has pre-set nutrient goals that automatically set you a reduced carbohydrate target in line with your calorie target.

• The 'Lower Carb' nutrient goal brings your carb target down while still remaining at a healthy level, and subsequently brings your protein target up.
• The 'Less Sugar' nutrient goal keeps your overall carb target at the normal level of 50%, but brings your sugar allowance down from 18% to 12% of your dietary energy. This promotes a diet lower in free sugars while still maintaining a normal carb intake made up of fibres and starches.

To set yourself the Lower Carb or Less Sugar nutrient goals in the Nutracheck app, tap the blue menu button next to the search bar in your diary, then select 'Nutrient Goals'. Choose the 'Lower Carb' or 'Less Sugar' goal from the list. Save your changes by tapping 'Set this goal'.

On the Nutracheck website, click 'Settings' from the menu at the top of your Diary page, then 'Set a nutrient goal'. Click the 'Lower Carb' or 'Less Sugar' goal from the selection, then click 'Apply Changes' to save your new settings.