No, I don’t think they did control for calories in. Certainly not all of them. One that I looked at simply said ‘there was no change in diet’. What does this mean though? It could well mean that they simply told participants to eat as normal. But studies that looked at appetite suppression through exercise often remark that people are unaware that they’re eating less.
I don’t have full access to the research articles though. I’m picking bits and pieces from various places that quote the studies and looking at the overviews so it’s hard to say for sure.
It’d be pretty cool if someone at T-Nation could check into this. They must have contacts etc that could do some more specific tests and studies? And they’d have access to full research papers I’m sure.
I think for most people the advice to do HIIT is sound. But understanding it better would help people to find the perfect balance for them as an individual.
[quote]Dr. Pangloss wrote:
“Not least, changes in eating habits. Some studies show that with most people high intensity training reduces appetite”
I didn’t read any of the studies, but did they (I hope) control for calories in? I can do a 10K on a Sunday morning and meet my friends for beer and burgers immediately afterwards. After any type of high intensity exercise, my appetite is shot for hours afterwards.
Having done a ton of low intensity and high intensity work, I always assumed it came down to the appetite-suppressant effects of the type of training chosen.[/quote]
Yes there are studies that controlled both.
And no idea what hiit or LISS you do I wish I reacted that way. I am ravenous doing either. Wait I am hungry just doing nothign too. Never mind.
At some point controlling for everything becomes futile because that is not how the real world works. That is why the best studies ONLY change one variable, being exercise. Let the people eat what they would eat, because that is how it works in the real world. Time and again in side by side exercise controlled studies, HIIT wins out on fat loss over LISS. Does it mean that it works for everyone? No, but it works for the majority, which is what we are talking about. Does it mean that people shouldn’t do LISS? NO! I personally think everyone should be able to go run a mile or three at a slow 8 minute pace, but that certainly doesn’t take any real training to get there.
[quote]susani wrote:
The article I linked to examines the studies in detail. It draws very different conclusions.[/quote]
Did you even read the study? They didn’t take groups and divide them in half and have one do HIIT and the other do LISS. The study you reference ONLY talks about EPOC. Like I said, none of that matters when time after time, when groups are assigned one or the other, the HIIT group ALWAYS has better body composition changes.
[quote]susani wrote:
A really good article here that explains how calorie burn can be reliably calculated by measuring oxygen consumption. It explains how they know that nothing is burning calories without a corresponding increase in oxygen consumption:
It also explains that there’s no good way to know whether those calories were burned from fat or carbs simply from the results.
Energy from carbohydrates could include things like gluconeogenesis where muscle tissue is broken down to amino acids and then converted into glucose.
Given the single measure of oxygen consumption, two persons could burn the exact amount of calories (per the oxygen consumption measure and related assumptions) but have different changes to body composition… one burns more fat than muscle; the other burns more muscle than fat, but they both, supposedly, burned the same number of calories.
There are also multiple energy stores within the body that make it somewhat more complex; was the energy source muscle glycogen? the phosphocreatine system? liver ketones? or was it from muscle catabolism or lipolysis?
Read the entire article Echestang - it’s over multiple pages. It doesn’t only talk about EPOC.
It’s pretty much given me the info I was looking for. It addresses the points you make.
It kind of ends the research/discussion for me. Still lots of unknowns, but I kind of feel that I have a better understanding of what IS known. Based upon this I’ll pretty much continue doing what I’ve been doing - instincts tie up with what the research says.
It’s been a really interesting discussion and everyone’s comments helped me track down the info I needed so thank you all!!
EDIT: LoRez - we posted at about the same time. I agree - lots of unanswered questions. But the bits that were baffling me (the contradictions) have been cleared up.
[quote]ryanbCXG wrote:
And no idea what hiit or LISS you do I wish I reacted that way. I am ravenous doing either. Wait I am hungry just doing nothign too. Never mind.
[/quote]
Hill sprints, track intervals, swimming intervals…pretty much any workout that is puke-inducing kills my appetite.
[quote]susani wrote:
The article I linked to examines the studies in detail. It draws very different conclusions.[/quote]
The post with that article has been deleted (just popped back in to find the link to send it to a friend!). I can understand why as it would be seen as a competitor site.
Basically, the article (pages and pages of it) looked in detail at the studies behind the claims of the massive calorie burn from HIIT and points out why the conclusions drawn are flawed. There is no such massive calorie burn (plenty of studies have proven that). The big danger in fitness professionals telling people otherwise is that they then think it’s OK to do 10 minute of HIIT then spend the rest of the day stuffing their faces with food! [I’ve honestly heard trainers telling people that after a high intensity workout their metabolism will be burning fat like a furnace and they can eat what they like!!]
The points made in the article explain the apparent conflict with the studies that disprove the theory that HIIT burns more calories. There is really no conflict - when the studies are looked at in more detail it’s apparent that there are other factors that explain the fat loss.
At the end of the day, ALL intensities and volumes of cardio can be highly effective. What works for one won’t work for another - many of us already knew that, but couldn’t explain why. Considerations are:
Your fitness levels - are you capable of doing a long run at sufficient intensity to burn calories? Are you capable of pushing hard enough in intervals to burn calories? How well do you recover ? One type of training might be more suitable for you simply because you’re able to recover from it (and therefore do enough in a week to make a difference).
Changes in appetite have been shown to be a factor. But everyone is different in this respect too. If one particular approach to training results in you eating less then it’s going to work extremely well for you regardless of how many calories it burns.
Do you like to do it? You won’t do something you hate therefore it won’t work.
Some of the scare stories re long duration cardio burning muscle - there is one commonly reported study that shows equal weight loss with long duration cardio and weight training, but with half the weight being muscle loss with the long duration cardio. However, this was FASTED cardio. A diet of just 800 calories a day. It proves that if you’re starving yourself strength training helps prevent muscle loss. But if you’re eating a good, satisfying volume of food with just a tiny calorie defecit cardo won’t start to burn protein until after about 90 minutes of continuous effort.
All of the studies need to be looked at in context. When you do that you see it’s not quite as simple as some would have us believe. In actual fact there are a very wide range of mixes of volume and intensity that will produce fantastic results if used in the right situation.
Other factors to consider include how long it’ll keep working for you. Apparently, the big benefits from HIIT have been shown to stop after 3 weeks (that surprised me!). The long, slow stuff also stops working as well as you get more accustomed to it.
Regular changes between different intensity levels, duration and modes of exercise will probably get best results. But not everyone is fit enough to do that, and not everyone wants to get fit.
