Which Form of Cardio Is Best For Fat Loss? Comparing HIIT vs. MICT

It’s time we settle this debate. It’s a battle as old as time itself. Is High Intensity Interval Training (HIIT) or Moderate Intensity Continuous Training (MICT) better for fat loss? Luckily, there was a recent meta-analysis published that provides some interesting insight on what the answer might be.

In this post, we will uncover what the met-analysis showed, what it means for you if you do cardio, recommendations on which method to do based on different circumstances and situations, and I’ll finish with putting in a case for cardiovascular training that you may have not considered. For the sake of ease, we’re going to lump HIIT and SIT (Sprint-Interval Training) together because they are similar forms of activity.

So everyone is up to speed, let’s quickly define the two terms. HIIT is typically a series of quick and intense bouts of training where an exercise is repeated either for reps or a certain amount of time while going all out and pushing near 100% with each interval. After the reps are met or time is up, you rest shortly for usually no more than a minute and then you do it again. Think of Crossfit or Tabata workouts for HIIT inspiration.

MICT, on the other hand, is your typical cardio. When people say the word ‘cardio’ you probably think of treadmills, StairMasters, and ellipticals. That’s MICT for the most part. Another part to it is that you don’t adjust the intensity of the exercise. So you stay on level 6 for 20 minutes, for example, without any significant changes.

Before we move on, I want to preface the discussion with this: Cardio is not necessary for fat loss or weight loss. If you’re doing cardio only for these reasons, you’re going to hate your gym life and make yourself miserable. There are a myriad of athletes who don’t do cardio and cut weight just fine such as powerlifters. Of course, if you’re prepping for a bodybuilding show, cardio is a bit more necessary but it’s a short-term endeavor which is more acceptable. Don’t feel pressured to do cardio to lose weight. Refer to my blog post on calories in, calories out to learn how to learn more how fat loss works and how to establish a caloric deficit to really get on track with your goals.

Okay, now that that’s out of the way, here we go. 

Good news is you can really pick whichever form you’d like, because the meta-analysis showed that both methods are equally effective for fat loss. An important point to note here is that the experiment was matched for energy expenditure. This means that the subjects doing HIIT burned the same amount of calories as the people doing MICT¹ during the experiment. Since each method is equally effective, then choosing which method you want to use could be based on things like the time spent on the activity, desired rigor, and personal preference.

On other important note to consider is the degree to which both methods were effective, which wasn’t a lot. Both HIIT and MICT contributed to a body fat reduction of less than 2% on their own. So yes, these methods can be used to elicit fat loss, but probably should not be used on their own. If you’re just doing cardio but not in a net calorie deficit, you won’t experience weight or fat loss. There may be some other benefits you see like improved mood, for example, but body comp. changes may not be seen. That’s why establishing a calorie deficit is nearly essential while incorporating weight training can increase the rate of loss while improving you health further and the way you look if you’re wanting to add muscle. Basically, you can’t just do cardio and not care about our diet or training and expect to shed pounds of fat. Cardio’s effect isn’t that significant!

Moving on.

For time constraints, HIIT is clearly the better option. You can knock out rigorous bouts of training using a seemingly endless variety of exercises in 5-10 minutes and then you’re done.

In addition, if your goal is to build some muscle, this is also a good method, as it may have some crossover effects. Think about it: you’re still likely lifting weights as part of HIIT, so you’re getting in some volume, although the benefit will be likely be minor, if any.

Another touted benefit of HIIT is potential appetite suppression. The meta-analysis pointed to some studies that showed there is a potential suppression of appetite when doing sprints or other forms of HIIT¹ when compared to MICT; although the research is inconclusive because other studies were cited that showed no change, so it’s still up in the air. For you, this is an excellent chance to experiment and see if that works for you or not!

One important note is that HIIT should be VERY hard. In the study, they define HIIT as “80-100% of peak heart rate or aerobic capacity”¹, meaning, this isn’t a bit of huffing and puffing, and then you’re done. HIIT is meant to very intense, so you should be bent over heaving and gasping for breath and possibly on the floor by the end of whatever you did.

It’s not a walk in the park. It’s more like a sprint in the park because a bear is chasing you and is right on your ass. This is a great transition to talk about the cons of HIIT, because there definitely are some!

HIIT is not for everyone. People who never trained before and overweight and obese individuals are perfectly capable of doing some form of HIIT, but it may not be the best option initially because it can come with an increased susceptibility to injury. For an obese person, the quick movements at near-maximal effort, jumping, etc. can be especially burdensome since they carry around a lot of extra weight, damaging their joints and/or bones. For a newbie, it’s a lot of extremely intense work hat they’re not used to, potentially scaring the person away from any form of exercise if you throw them in the deep end at the beginning.

Last con is that cardio is not weight training, and so precautions should be taken if you are weight training to ensure that your HIIT is not interfering with your lifting performance. Some people get very sore from HIIT, which could hinder their lifts. Plan accordingly and give yourself enough time to recover from HIIT if you also plan on lifting weights.

This is not to say no obese person or newbie should never start with HIIT. Some people enjoy the challenge and feeling the burn in their lungs from the get-go and can do it safely; others need to ease into it. Either one is fine, the safety is what’s ultimately important, so you don’t bust your ass trying to do a kettlebell swing.

We can quickly breeze over MICT because it’s bascially warranted whenever HIIT isn’t appropriate as mentioned in the previous paragraphs above.

MICT is the better option if you simply enjoy it more and don’t have time contraints. If you don’t like feeling like you’re about to die (exaggeration) from your cardio, then HIIT probably isn’t up your alley, not to say you can’t work up to getting better a tolerating it.

MICT is also better if you’re dealing with some type of injury. If you have a back injury that prevents you from bending over or causes pain with rotating your torso, MICT has plenty of ways where you can still do cardio without those problems arising.

If you’re overweight, obese, or are new to the gym/cardio, I recommend MICT because it’s a great way to ease into exercise without overloading to dangerous levels of work.

I don’t recommend MICT-or any form of cardio for that matter-if you think that it’s the only way to lose weight, by running on a treadmill for hours. As mentioned before, cardio is not necessary for fat loss. All these reasons for cardio should be supported by the fact you enjoy the training, not because you think cardio is the only way to lose weight.

In short, HIIT and MICT have both been equally shown to influence fat and weight loss (to a small degree). Cardio-however you do it-is simply another tool in your fitness tool belt. You can decide to use it or not. HIIT is good for time constraints, augmenting your lifting, and possibly for appetite suppression. MICT is effective for beginners or overweight and obese people, those concerned that HIIT may interfere with their weight-training sessions, and those who just enjoy getting in some movement without feeling like death.

Have some thoughts on cardio? Comment below and tell me what you think!

References

¹Keating, S. E., Johnson, N. A., Mielke, G. I., and Coombes, J. S. (2017A systematic review and meta‐analysis of interval training versus moderate‐intensity continuous training on body adiposityObesity Reviews18: 943–964. doi: 10.1111/obr.12536.

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Diet Types & Which Work For Weight Loss? Part 2

Welcome back. I missed you. We’re here to finish our discussion on the different types of diets that are out there and to determine which work for weight loss. If you haven’t read part one, we go over what each diet entails and what makes it different from the others. Read it here before reading this so you don’t get lost. Got your favorite reading food ready? Good! Let’s begin.

Low Energy and Very Low Energy Diets

Often, this is the approach many will take when trying to lose weight. They think cutting calories drastically will lead to weight loss. Don’t get me wrong, it absolutely will; however, not all that weight lost will be fat. Up to 25% of the weight lost on these diets can be from muscle aka lean mass1. While many think muscles are only important for bodybuilders, they’re essential for everyone. They help us live our lives injury-free and perform the basic movements that we do without a second thought. Love your muscles. Say thank you by not starving them.

Interestingly, LED & VLED have been able to preserve lean mass on untrained subjects. The research participants were put on a resistance training program and were able to either maintain or increase lean mass2. Keep in mind, these people were untrained and would likely have preserved or built muscle regardless of what happened to them. While interesting, It’s certainly not a reason to try these diets. Being in a chronic (persistent) severe caloric restriction such as LED or VLED can lead to issues arising from low protein intake. Although your calories may consist of mostly protein on these diets, the total amount relative to your body weight matters. On these diets, it’s difficult to acquire that much protein in your diet while staying at such a low amount of calories

Really, one of the only reasons you should be on this diet is if you’re severely obese and you need to drop weight ASAP. Care professionals will often start the patients on a LED or VLED for the first few weeks to begin the loss process. Research shows that this initial restriction actually improves long-term weight loss success3. Over time, however, the drop in calories becomes less aggressive so the patient can slowly increase their metabolism while still dropping weight. They don’t want the patient to be maintaining on the very low calories they started with when they can have them be just as better off on more calories.

Low Fat and Very Low Fat Diets

Low fat diets were all the rage a couple decades ago; but do they actually help with weight loss? Unfortunately, there is little research on VLFD, and none of which cover body composition. These diets are successful in promoting weight loss when intake of fat is reduced from the diet4. Duh. This goes back to what I said in part one. A caloric deficit will usually lead to weight loss.

Although little research has been done on VLFD, there has been some studies that show this diet strategy is difficult to adhere to. When told to consume at most 20% of total calories from fat, subjects were actually consuming around 26-28%, suggesting that it is difficult to stick this diet for varying reasons5. One reason could be that food containing fat is tasty, so people will eat more. Also, lots of foods contain fat, which may make it difficult to reach other macronutrient targets without going over their fat allotment. From this viewpoint, VLFD may not be the best option since you will likely have to go over anyways to satisfy protein and carb intake.

Low Carb and Very Low Carb Diets

There was a recent meta-analysis conducted that did show that LCD diets, especially VLCD, resulted in more fat loss than a normal-level carbohydrate diet6. The findings from this meta-analysis may not be able to be extrapolated (applied to) the general public, as the subjects were obese, and so fat loss was likely regardless of the diet if their calories were being monitored. Still, LCD are very popular and many seem to be able to stick to and enjoy them. I would just say make sure you’re getting in your daily requirement for fiber and fruits and vegetables for the vitamins and minerals if you decide to go low carb. Carbs are still important!

Ketogenic Diets

Here we go. A lot of people think that KD is magic and better than other diets because the decreased level of insulin activity. Carbohydrates are the major trigger for insulin to be secreted. For those who don’t know, insulin acts as a “gatekeeper” between your body’s cells and glucose. Once insulin is secreted, it allows for cells to uptake glucose and provide energy to your body. People think that since carbs are not being consumed as much, that less energy and fat is being stored, hence, relying on body fat for energy; however, when put to the test in the lab, this did not hold to be true.

Research shows that, while a KD can induce weight loss, the net amount is not superior to a normal high-carb, energy-restricted diet7. Does this mean that KD doesn’t work? Absolutely not. It simply means that one is not better than the other. This is good news because it allows people flexibility to select what they want and be confident that if they stick to the diet’s protocols, they should see results!

One interesting advantage of a KD is that it may be appetite suppressing. When subjects were allowed to eat as much as they wanted, unrestricted, the KD group had an average decrease of 294 calories consumed per day8. The reason as to why there was a drop in calories is still unknown. Perhaps because more protein was consumed. Protein helps will fullness, and so may have led to the participants getting full quicker.

High Protein Diets

High protein diets have consistently been shown to be beneficial for weight loss. Protein is the most satiating macronutrient. It helps you feel full, and so you (should) eat less than normal, prompting weight loss. But what constitutes a high protein diet and when is it too much? Some work has shown that consuming about two times the Recommended Dietary Allowance (RDA) is optimal for preserving lean mass while simultaneously reducing fat mass9,10. Anything higher has not shown any benefits for this purpose11. Double the RDA amount is roughly 1.6 grams/kilogram bodyweight (0.7 grams/pound bodyweight).

In Summary

All of these diet strategies can work for losing weight. It is up to you to decide which one you like and what you will stick to. Remember, it’s not the diet that’s going to trigger weight loss, it’s the caloric deficit. That is what matters when we’re concerned with losing weight. Personally, I would not go with LED, VLED, or VLFD. These diets are going to be difficult to stick to, and/or you may not acquire all the necessary nutrients that you need in the proper amounts. I do not have an issue with the other strategies as long as they are being adhered to and you are enjoying the process. Once again, dieting should not be a hellish process if you’re simply trying to lose some weight for an upcoming event or you’re starting a journey to improve your health.

Adopt a healthy, happy relationship with food, and you’ll find that losing weight can be enjoyable and your life does not have to be centered around food! Still have questions? Let me know in the comments below! Thanks for reading! Share this with others who think there are magical diets!

References

1Saris W. Very-low-calorie diets and sustained weight loss. Obes Res. 2001;9 Suppl 4:295S–301S.

2Bryner R, Ullrich I, Sauers J, Donley D, Hornsby G, Kolar M, et al. Effects of resistance vs. aerobic training combined with an 800 calorie liquid diet on lean body mass and resting metabolic rate. J Am Coll Nutr. 1999;18(2):115–21.

3Nackers L, Ross K, Perri M. The association between rate of initial weight loss and long-term success in obesity treatment: does slow and steady win the race? Int J Behav Med. 2010;17(3):161–7.

4Hooper LAA, Bunn D, Brown T, Summerbell CD, Skeaff CM. Effects of total fat intake on body weight. Cochrane Database Syst Rev. 2015;7(8):CD011834.

5De Souza R, Bray G, Carey V, Hall K, LeBoff M, Loria C, et al. Effects of 4 weight-loss diets differing in fat, protein, and carbohydrate on fat mass, lean mass, visceral adipose tissue, and hepatic fat: results from the POUNDS LOST trial. Am J Clin Nutr. 2012;95(3):614–25.

6Hashimoto Y, Fukuda T, Oyabu C, Tanaka M, Asano M, Yamazaki M, et al. Impact of low-carbohydrate diet on body composition: meta-analysis of randomized controlled studies. Obes Rev. 2016;17(6):499–509.

7Hall K, Chen K, Guo J, Lam Y, Leibel R, Mayer L, et al. Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. Am J Clin Nutr. 2016;104(2):324–33.

8Johnstone A, Horgan G, Murison S, Bremner D, Lobley G. Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum. Am J Clin Nutr. 2008;87(1):44–55.

9Layman D, Evans E, Erickson D, Seyler J, Weber J, Bagshaw D, et al. A moderate-protein diet produces sustained weight loss and long-term changes in body composition and blood lipids in obese adults. J Nutr. 2009;139(3):514–21.

10Layman D, Evans E, Baum J, Seyler J, Erickson D, Boileau R. Dietary protein and exercise have additive effects on body composition during weight loss in adult women. J Nutr. 2005;135(8):1903–10.

11Pasiakos S, Cao J, Margolis L, Sauter E, Whigham L, McClung J, et al. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB J. 2013;27(9):3837–47.

Diet Types & Which Work For Weight Loss? Part 1

Low carb, low fat, ketogenic…what do these terms mean? What the hell works? Turns out most of them will work if you stick to it *gasp*. There is a lot of frustration when it comes to selecting a diet to lose weight. Oftentimes, on the internet, you’ll find some guru jackass touting the superiority of a low-carb diet or ketogenic or some other type of diet. They also will typically say that this is the only way that works to lose weight and be healthy. A recent position statement by the International Society of Sports Nutrition (ISSN) begs to differ.

The ISSN is a non-profit academic organization dedicated to providing credible and evidence-based nutrition information. They’re the cream of the crop for who you can trust for accurate information. Last month, they released a comprehensive statement-that I’m still reading through-all about diets and body composition. In their statement, they present the research and their interpretation of it on an array of topics relating to diets, dieting, and body composition.

By the way, body composition refers to the literal structure or makeup of your body in terms of how much muscle, fat, water, and other “ingredients” are in your body. A bodybuilder will have a higher percentage of muscle compared to fat and vice versa for a more sedentary person, typically.

“But I don’t have time to read the statement, what does it say?

Well, things that are often great don’t come easy, so you’ll have to put in time to be great at something. But enough life lessons. I know not everyone-unfortunately-isn’t as enthusiastic about reading this stuff as I am, so here are some of the findings summed up from the position statement. In part one of this series, we are going to simply define the different diets and get familiar with them. I will also provide a quick opinion of my thoughts on why these diets work for weight loss. In part two, we will discuss the actual data and the nitty gritty of it all.

Before I begin, I want to say that all of these approaches, when performed properly, can and will lead to weight loss. It’s up to you to decide which approach you want based on your ability to stick with it and whether or not you enjoy it. Dieting shouldn’t be a hellish process, so pick what’s best for you. There’s no one single diet that works for everyone. Okay, without further adieu, Let’s go:

Low Energy Diets and Very Low Energy Diets (LED & VLED)

These two diet types are simple. Consume a small amount of calories to lose weight. LED ranges from 800-1200 calories while VLED is usually defined as 400-800 calories. To be frank, you don’t need research studies to say that these diet types will (typically) cause weight loss. Most people don’t consume such low levels of calories and will most likely begin to lose if they adopt this approach. If someone goes on a VLED diet, the majority of the calories will have to come from protein. You can read more about why that’s the case here.

Low Fat Diets and Very Low Fat Diets (LFD & VLFD)

Keep this in mind as we move forward, the rest of the low- diets do not mean low calorie. You can be low-fat or low-carb or low-whatever, and still consume a lot of calories. They’re not the same thing.

Okay!

Great. I’m glad you understand. LFD & VLFD usually mean 20-35% and 10-20%, respectively, of your total calories. Often, a low-fat diet can also be thought of as a high-carb diet because that’s usually the case. If the fat is low, the carbs will often be high to make up for the lack of energy-providing sources from fat.

My reasoning for why LFD/VLFD work is because dietary fat is very easy to consume in excess. Let’s take oils. One tiny tablespoon quickly adds up to 126 calories (14g fat x 9 calories/g of fat=126). Let’s be honest, most of us-except me-aren’t measuring their oil usage. So, you likely get a lot more calories from oil than you think you are.

When you decide to go low fat, you’ll likely reduce your total caloric intake since fat is very calorie-dense. This is what will drive the weight loss, fewer calories consumed daily². Fat isn’t evil. You’re not losing weight because you’re consuming less fat, you’re losing weight because less calories are being eaten.

Get it? Got it? Good.

Low Carb Diets & Very Low Carb Diets (LCD & VLCD)

Unfortunately, there isn’t an agreed-upon definition for what a low carb diet consists of. Some think it means less than 45% of your calories comes from carbs while others think low carb is less than 50g per day. I think a safe bet would be anywhere below 45% total calories then adjust it from there based on what you prefer.

Low-carb diets, in my opinion, are the most popular form of dieting as of right now. It’s easy to do because you can usually just eat less of what you’re eating now and not have to make too dramatic of lifestyle changes.

I think the reason it works is once again, less calories being consumed overall in the diet. There isn’t any magical process that happens in your body when you consume less carbs.

I think people believe that because they may adopt healthier habits such as having fruit as a snack instead of cookies or eating more vegetables because they are actively trying to lose weight whereas before, they may not have cared as much. It’s not magic, just more whole foods that contain vitamins, minerals, and fiber. The good stuff!

Ketogenic Diets (KD)

Technically, this is a form of low carb dieting; however, an interesting process occurs in your body to properly call it a ketogenic diet. KD is defined as having a max of 50g carbs in your diet daily or 10% of your total calories. 1.2-1.5 g/kg bodyweight from protein and the remainder is fat, which is roughly 60-80% of your total calories3,4. If you’re an athlete or lifter, your protein should be a bit higher than that to preserve lean mass.

In order to properly do a ketogenic diet, a process known as ketosis needs to occur. Ketosis occurs from excess fat breakdown due to glucose (carbohydrate) not being available to use. An acid known as a ketone begins to get synthesized to replace the glucose that isn’t being made quickly enough from fat; however, this is a process that can take a varying amount of time for the body and brain to adjust to. People will often complain of sluggishness or brain fog when starting a KD. Over time, your body will adjust to being in constant ketosis and you can function normally.

Side note: your body creates ketones daily, but not an amount high enough to trigger ketosis when your carbs are a primary contributor to your diet. The low intake of carbs is the only way to trigger ketosis.

Once again, ketogenic diets are not magic. They’re successful mostly because carbs are the biggest contributor to calorie consumption. When you reduce your intake drastically, coupled with a possible increase in protein (protein is very satiating), you get a net decrease in calories taken in from your diet. Hence, weight loss! Yay!

High Protein Diets (HPD)

HPD are generally defined as being at 25% of total calories or exceeding that level of intake.

There isn’t much to be said about it right now until part two, but my opinion on why they work is because protein is the most satiating macronutrient of the three. This means that protein is filling and helps with feeling full. Due to this, people don’t want to eat as much and consume less calories. Deja vu, right?

Stay tuned for part two! We’re going to look at what the research says about these diet methods and whether some are better than others and suggestions for when to use one over another!

References

1https://jissn.biomedcentral.com/articles/10.1186/s12970-017-0174-y

2Hooper LAA, Bunn D, Brown T, Summerbell CD, Skeaff CM. Effects of total fat intake on body weight. Cochrane Database Syst Rev. 2015;7(8):CD011834.

3Westman E, Feinman R, Mavropoulos J, Vernon M, Volek J, Wortman J, et al. Low-carbohydrate nutrition and metabolism. Am J Clin Nutr. 2007;86(2):276–84.

4Paoli A. Ketogenic diet for obesity: friend or foe? Int J Environ Res Public Health. 2014;11(2):2092–107.