Devlin Brown at the water cooler: How high-intensity exercise can keep hunger at bay

I joined the gym to lose weight but ever since I started training I am always hungry. Am I doing something wrong?

It’s difficult, if not impossible, to lose weight when you are constantly hungry. Prof Tim Noakes has, on a number of occasions, said something similar.

The point is that you can stick to a regimen for only so long before the physiology of being hungry overwhelms your resolve and you give in to the most basic urge to eat. 

Of course, there is more to it. Noakes also refers to the inevitable rebound that happens when the “diet” stops. You should know by now, as a loyal reader, that we are slaves to our hormones.   

It’s like traffic lights on Beyers Naudé. You can convince yourself you’ll get to your meeting on time, you can leave early, you can even play your favourite music and sing at the top of your lungs. But come hell or high water, every second or third light will be out, resulting in a chaotic hodgepodge of death-defying vehicular roulette and long queues of impatient Joburgers.

Hormones are the same — you can do all you want to convince yourself that 2,000 calories from jam doughnuts are the same as 2,000 calories from rump steak, but eventually your pancreas will remind you about the danger of repeated insulin dumps and you’ll incrementally loosen your belt on the journey towards type-2 diabetes. 

Back to always being hungry when you exercise. It seems to make sense — the more you exercise the more you’ll want to eat. The more you drive, the more petrol your car needs. Funny thing is, a new study released a few days ago suggests that those who claim that exercise alone can’t result in sustainable weight loss — because you’ll give in to resultant hunger — may not be entirely right.

A study published in the Journal of the Endocrine Society on October 24 2024, found that how you train affects how hungry you become — especially if you are a woman. According to the authors, high-intensity training — that is, beyond your lactate threshold, results in suppression of the “hunger hormone” ghrelin. 

The implication is that when you train at a super-high intensity, your appetite decreases. If this type of training is done regularly it could be a sustainable way of losing weight by eating less while exercising more.

Quoted in SciTechDaily, one of the authors, Kara Anderson from the University of Virginia and the University of Virginia Health System in Charlottesville, says: “We found that high-intensity exercise suppressed ghrelin levels more than moderate-intensity exercise. In addition, we found that individuals felt ‘less hungry’ after high-intensity exercise compared to moderate-intensity exercise.”

Most studies in the past focused on men, and so in this one there is an almost 50-50 split. The difficulty is that the sample size is tiny: 14. Far more research is needed.

The participants fasted overnight — I always find it is best not to eat while sleeping — and then completed exercises at varying intensities measured by blood lactate levels. They then self-reported on their appetite. 

The female participants, say the authors, had higher levels of total ghrelin at baseline compared to their male counterparts, but females demonstrated “significantly reduced AG [acylated ghrelin]” following intense exercise.

The authors found that moderate and low-intensity exercise did not reduce ghrelin and rather had a net increase effect. In other words, that kind of exercise leads to being more hungry.

“Our research suggests that high-intensity exercise may be important for appetite suppression, which can be particularly useful as part of a weight loss programme,” says Anderson.

It is obvious that you need to be mindful about what you eat. If you are hungry you cannot starve yourself. That causes another hormonal cascade that is a whole new topic. If you are hungry, eat mindfully. 

Anecdotally and entirely unscientific, in my experience jogging does support weight loss (and it makes you fit). However, when I add high-intensity training to my regimen I lose more body fat and hold onto more muscle. I know this to be true for me, but sometimes I just don’t feel like it. That’s food for thought.