Are high glycaemic index foods bad for you?

Welcome to the 33rd episode of Vegetarian Health and Longevity from Hurry The Food Up and Sports Nutritionist James LeBaigue.

Blood sugar spikes, insulin resistance, weight gain. All terms which worry people, and I get why.

Certain foods often get a bad rap for causing or being associated with these terms, and have been linked with issues like diabetes and obesity

There’s a lot of debate, between the everyday person and professionals, about whether they’re good or bad for you.

Some people say you should avoid them at all costs, while others suggest they can actually be useful in certain situations.

What am I talking about? High glycaemic index foods, also known as high GI foods. In this podcast episode, I’ll break down what these foods really are, why some people worry about them, and why others see them as helpful tools.

By the end, you’ll have a better idea of what high GI foods are and whether they fit into your daily life.

You can find it on YouTube below or you can listen to it here on your favourite provider.

If you missed last week’s about the one diet you can always rely on for weight loss, then you can listen to or read it here.

What are high glycaemic index foods?

So, let’s start by clarifying what I mean by the “glycaemic index” (or GI, for short). If you’re not familiar with the term, you’re definitely not alone! 

It’s a term that describes how much a particular food impacts your blood sugar level. Blood sugar, or blood glucose, is something your body controls very carefully, keeping it within a specific range – usually between 4 and 7 millimoles per litre.

When your blood sugar gets too high or too low, your body steps in to adjust it, using processes that can either bring it up or down. 

Glucose is a simple carbohydrate, and it’s actually the main form of energy, along with fat, that our bodies use, both in everyday activities and during exercise. 

So it makes sense that foods with a bigger effect on blood glucose tend to be those higher in carbohydrates. Foods rich in protein or fat have a lower glycaemic impact, not because they contain little or no carbohydrate, but because the presence of other nutrients slows the absorption of any carbohydrate present. This slower digestion rate reduces the glycaemic index of these foods.

The glycaemic index itself is a way to rank foods based on their impact on blood sugar, using a scale of 0 to 100. Pure glucose is the standard, and it sits at the top of the scale at 100, as does white bread, which is very similar in its effect on blood sugar. 

In general, foods with easily accessible glucose, like white bread, rank higher on the GI scale because they require very little effort for your body to digest and absorb, meaning they can affect your blood sugar very quickly and noticeably.

On the other end, foods with a lower GI take longer to digest and release glucose into the bloodstream more gradually. This leads to a slower, more controlled rise in blood sugar.

Are high glycaemic index foods bad for you?

So why do high GI foods get such a bad reputation?

There are a couple of main concerns people have. First, high GI foods can cause a rapid rise in blood sugar, meaning your body has to release a lot of insulin to bring it back down. Some worry that if you eat high GI foods often, this constant demand for insulin could overwork your pancreas and potentially contribute to diabetes.

The second concern is that these foods tend to lack nutrients like fibre, protein, healthy fats, and important vitamins and minerals. This means that eating too many high GI foods can lead to a diet that isn’t balanced or nutritious, which isn’t ideal for overall health.

To understand this topic properly, we need to dive into these points.

First, it’s important to understand that, unless you have diabetes, the GI of a food alone isn’t a measure of whether it’s good or bad. The body’s response to carbohydrate-heavy foods by releasing insulin is actually a normal and healthy process, and it’s not something most people need to worry about. There’s very little evidence to show that high GI foods directly cause obesity, type 2 diabetes, or other major health issues – outside of perhaps some dental problems if you don’t have good oral care.

While high GI foods can contribute to overeating because they’re less filling, they don’t directly cause weight gain or diabetes. 

The second concern about high GI foods lacking nutrients is largely true. These foods are often processed and high in simple carbs, meaning they don’t usually offer much fibre or protein. But that doesn’t necessarily make them bad for you and context is way more important here.

As long as your overall diet includes plenty of nutrient-rich, unprocessed foods, having some high GI foods here and there isn’t likely to be an issue. In other words, it’s about balance, something you might have heard as a theme through other podcast episode.

There are three times when high GI foods can be really useful: before, during, and after a workout.

Before we get into those, if you’re interested in losing weight as a vegetarian, you should check out The Vegetarian Protein Fix, our flagship weight loss membership. We help vegetarians lose weight safely and healthily, all while being able to eat the food that they love. You can try out a free week’s meal plan which is like those in TVPF, and you can find that at htfu.com/try. It’s got a full week of meals scheduled, shopping lists and step by step instructions. So head to htfu.com/try and get started today.

Using High GI Foods Before Exercise

If you’ve ever had tummy issues during a workout, you’re not alone. Many people experience bloating, cramps, or even diarrhoea during exercise, and this is often due to poor food choices. 

One way to reduce the risk is by choosing high GI foods before your workout. Since they’re easy to digest, they’re less likely to stick around in your stomach and cause discomfort.

For example, let’s say you normally have a handful of nuts before running. 

Nuts are a healthy snack choice, but they’re high in fibre and fat, both of which slow down digestion, and that food is much more likely to still be in your GI tract when you run. 

If you had this as a snack, chances are you’d get stomach upset when running, especially if you did high intensity exercise.

I chose this as an example because I had a client who had been doing this, and making a swap solved their issues.

Switching to something like white toast and jam can make a big difference, as it digests faster and is less likely to cause tummy troubles. So while it’s a high GI snack which could be seen as unhealthy, in the right context it’s fantastic.

Using High GI Foods During Exercise

When you’re in the middle of a workout, the last thing you want is to wait for your body to break down complex foods. This is where high GI foods shine, especially during longer or more intense exercise sessions. Sports drinks, energy gels, and other high GI snacks are great during workouts because they provide quick, accessible energy without sitting heavy in your digestive tract. 

And remember that whole insulin spike concern? During exercise, your body is incredibly efficient at using carbohydrate for energy and can absorb it directly. 

This means even if you’re consuming quite a bit of sugar during exercise, it’s being used for fuel rather than causing issues with blood sugar.

Fun fact, I work with triathletes who regularly consume over 100g of carbohydrate per hour. In context, that’s more 6 tablespoons of sugar per hour when exercising, and it’s the right thing to do. Kind of mind-blowing, right? Context is so important.

Using High GI Foods for Recovery

After a tough workout, your body needs to replenish its glycogen stores – which is its stored form of glucose in your muscles and liver. 

High GI foods can be perfect for this because they quickly raise blood glucose, helping to speed up the resynthesis process. If you’ve had a particularly intense session, opting for high GI foods like white bread, pasta or rice, sports drinks or fruit like banana can be a super way to improve your recovery. 

However, I should say that you don’t need to load up on high GI foods after every workout. For easy or short sessions, just have a balanced meal with a good source of protein and some carbs, ideally within 45 minutes of finishing. 

It’s only after intense or long sessions that you need to prioritise faster recovery, which is where high GI foods come into their own.

So while high GI foods are often labelled as “bad” or “unhealthy,” it’s really about how and when you use them. When used correctly, especially around exercise, they can be a great tool for energy and recovery. Like most things in nutrition, context is everything, and understanding the bigger picture is key.

Even if you eat them occasionally and you aren’t exercising, that’s ok too. It’s just more of an issue if they feature regularly in your diet in place of more nutritious food, or contribute to overeating and excess calories.

So I hope this gave you some clarity on the whole high GI food debate. If it did, then please give the podcast a quick review on whatever platform you’re listening on. 

It helps the podcast to spread to more like minded people like you, and it’ll only take a moment. Thanks so much, and we’ll speak soon.

---

And finally, here is the easiest way to sign up to try our meal plans (free).

And a list of our vegetarian meal plans (also all free).

And finally finally: More vegetarian podcasts this way!