Road Fan

I have a friend telling me about his Optavia weight loss plan, and it sounds interesting. I asked the Optavia guy about yoga and aerobic exercise, and they do not encourage either. Can this be right? The plan is based on fat-burning. Is it healthy to force the body into fat burning? You eat at a very low calorie level to consume glycogen, then your body starts consuming fat. No mention of using exercise to consume glycogen.

It seems odd, but it seems to work.

Is it safe and not risky?

MoAlpha

These rather drastic energy restriction diet plans generally discourage exercise. They drive you down below the energy intake required for basal function, and glycogen stores effectively disappear within a day under those conditions. At that point, any exercise has to be fueled with fat and conversion of protein to glucose in the liver, which is not sustainable. I have heard from people who've done these programs, that exercise is very, very difficult.

Fat burning under these conditions = ketosis and yes, it's healthy enough, at least over the periods it's been studied, as long as basic energy and micronutrient needs are met. At least in animals, energy restriction results in increased lifespan. Anyone who wants to exercise while doing this should add back enough carbohydrate to fuel it.

Chuck M 

I have nothing really useful to add to the question. But my wife wanted to try this. She talked me into doing it as well. Most of the items like bagged snacks or bars IMHO tasted good initially, but by the time the package was finished, tasted awful. Items that were heated such as soups were better. The biggest thing I didn’t like was the Optavia person my wife found was a pest and I had to block her email and on social media.

However I will say that the lady that suggested it to my wife lost a lot of weight doing it and has kept it off. But any diet that keeps me from running, biking or other exercise is not for me.

Road Fan

Wow, thanks! Yes, that's exactly how they say it works but they say nothing about adding carbs to support workouts. This is already a step forward! The Optavia people are not giving responses this pertinent!

So some new questions come to mind:

1. How does one estimate the amount of extra carbohydrate needed to take on a particular level of exercise?
2, And how does carb burning relate to training zone or intensity?
3. Are there foods with enough extra carbohydrates to be useful, but very low protein, fats and sugar? From all the writing about cyclists' diet, I think protein "makes" glycogen, and it looks like I would get enough protein in the Optavia diet, so I don't want high-protein supplements.

Road Fan

I've actually bought the box of foods, and I didn't doubt about cycling until I realized the first thing this low calorie diet is intended to do is to force all the glycogen to be consumed. Since wife and I have just planned to start significant daily walks working up to three hilly miles a day mixed with mostly-conversational MUP rides. She's more of a speed demon than I am, mainly due to her greater practice and much better power to weight ratio - hence I have instructions to lose weight. But our MUPs have hills can sometimes drive you into HIIT zones, so I think it is not normal to have burned off all my glycogen at the start of a bike ride.

The coach is very helpful but is also a busy engineer who does not have time to become an expert on the metabolism of endurance/high-energy athletics. His goals in working out are to do leisurely stuff in the summer. Wife and I have targeted some tours for the summer and to use our MUPs for training.

MoAlpha

Yeah, clearly this is not something the corporate weight loss program folks want to get into and I can't blame them. Their job is to slim fat folks down and cutting their intake to the bone is the most efficient way to do it. Once you add exercise and try to fuel it, you're on a whole different approach to weight loss.

As you imply in question two, duration and intensity determine the carb requirement. At low intensities when things are pretty aerobic, fat accounts for a substantial fraction of the energy consumed and this decreases with intensity. All the info required for "carb periodization" is out there and readily found, but if I wanted to do it, I'd probably pay for a consult with a reputable sports nutritionist to set up my requirements.

I get most of my added (fuel) carbs from brown rice, which is pretty healthy, but, again, once you add something like that, you're on a whole different diet.

You need a ****-ton of protein on these radical diets a. because it's all there is if you're avoiding fat and carbs and b. because you are in a constant state of starvation and burning muscle protein all the time. Protein can be converted to glucose (carbohydrate) in the liver, but glycogen comes from circulating glucose and not directly from protein. Also the glucose produced by the liver from protein is not enough to make glycogen and is largely taken up by the brain, heart, etc. which have constant requirements for glucose and can't store it.

terrymorse 

Here's a graph that shows typical carb- and fat-burning rates by exercise levels:


That "MFO" stands for "Maximal Fat Oxidation" -- the exercise zone where fat burning is at its highest.

MoAlpha

That looks like it’s from pretty elite endurance athletes. I doubt I’m that good a fat burner.

RH Clark

I've lost a lot of weight and kept it off 4 years. I don't trust any industry associated with weight loss whether it's drugs, supplements, or premade meals. Low carb whole food and IM fasting combined with cycling
worked for me.

wolfchild

Any weight loss plan that encourages severe caloric deficit and discourages aerobic exercise is BS. .Run away from it because it's just another lie.

MoAlpha

If conservative approaches to weight loss worked for most people we wouldn’t have a pandemic of obesity and a plague of diet hustlers.

PeteHski

You could argue the same point about commercial "fad" diets too. Pretty much everyone I know who has been on a "commercial" diet program has lost weight initially, only to end up back at square one within a year.

I think the key question to ask yourself with any diet is "can I realistically sustain this diet for the rest of my life?"

A quick Google of the Optavia diet came up with this scathing review:-

"https://www.goodhousekeeping.com/health/diet-nutrition/a28436828/what-is-optavia-diet/"

So basically a high protein, extreme calorie deficient diet based on processed "fuelings". As the review says, you would be better off looking for more natural sources of protein.

But trying to be positive, maybe it's a way of getting off a load of weight initially before moving on to a more sustainable, healthy diet and exercise regime.

MoAlpha

You are right, of course. The entire problem is behavioral and commercially programmed diets with coaches and mandatory purchases of overpriced protein snacks are one, largely temporary, solution. People do drop a lot of weight on them, but tend to rebound and yo-yo and spend a lot of money. And yes, one could do the whole thing one’s self, with enough knowledge, time, and discipline. Are they a net evil? I don’t think so, at least for those who can afford them. I save my anger for those who impute stupidity, laziness, and moral failure to people who can’t lose weight the way those people think they should.

PeteHski

I think it's a lot easier now to formulate a reasonable DIY healthy diet as the required info is easily accessible and tools for calorie counting/nutritional balance are readily available in simple, low cost phone apps. If I was going to throw money at it, I would invest in the services of a qualified nutritionist or an experienced nutrition coach, preferably one with experience of endurance sports.

But I can see the appeal of a commercial diet plan for some. It's probably going to be the quickest way of losing significant weight initially, but almost certainly not a long-term solution. So maybe the answer is to do both? Use a commercial diet plan to kick-start the weight loss and then work out a sustainable long-term plan, with or without expert nutritional guidance.

MoAlpha

That's probably what I would do too. It's worth noting, however, that, at least in the US, there are no official qualifications to be a nutritionist or nutrition coach and these individuals, effective as many of them may be, are operating in the same market as the corporate diet people.

PeteHski

In the UK there are degree level professional nutritionists and trained nutrition coaches. It's the latter that tend to be more public facing, offering diet mentoring services etc. Personally I would stay well away from any company pushing their own processed food & supplements. I would be looking for advice based on real foods, healthy eating and exercise.

Jughed

It takes a few months to become efficient at burning fat.

I use a specific low/no carb diet to treat a disease - I am not in any way an elite athlete. But after a few months of switching my body from glycogen based to fat based - I can ride in that Zone 2, low Zone 3 range all day without food. And I'm starting the ride with little or no glycogen stores. As my fitness improves and my Z2/Z3 range trends higher - my fat burning keeps up.

For longer rides that will have some intense efforts, or for interval training, I simply add 30-40 grams of carbs per hour. When you go above that low Z3 threshold, you will burn glycogen, so you need to replace what you burn or you will bonk out. If I'm doing a very hard ride - like 1.5-2 hours of tempo(higher Z3) or a big climbing effort - I will preload with some carbs and eat 50-60 per hour.

But I eat plenty of calories, plenty. And the weight keeps coming off, slow and steady - no fast solution or products. Just good quality whole foods, without carbs.

Steamer

This has been my approach as well. Not complicated, but it does require a certain level of vigilance to keep carbs and sugar from sneaking in. Requires more time spent the kitchen too. But it's either this or metabolic disease.

Steamer

My experience as well.

Becoming highly bonk resistant at endurance pace was not why I changed my diet to low carb, but it certainly was a pleasant side-effect. Carbs consumed during exercise won't spike insulin, but they are to be avoided otherwise. As essentially you suggested though, you don't need the carbs unless you are doing high intensity for a couple hours or more.

When I eat, I always eat till I am full. To do anything less encourages metabolism to fall.

MoAlpha

Good job, but you still don't have numbers like the chart above, because no one does.

It bothered me, so I tried to track it down and it's a modification of a theoretical plot from Brooks and Mercier in a very influential opinion paper from 1994, where they introduced the model. All good, except the real world data look like this:



https://www.mdpi.com/2072-6643/14/8/1605 (for the academics, please pardon the MDPI citation)

where fat oxidation never accounts for more than 60% of energy output and the crossover point is somewhere near 55% VO2max.

Jughed

So I'm not a big chart reader type... here are my numbers. I think they fall right in between.

VO2 max watts are 325+/-, threshold 252, upper Z2/low Z3 195-210.

I can ride at 200+/-W for at least 1.5+ hours on my typical 10-15 carb per day diet. No carbs before, during or after the ride. That's right at 61% of my VO2 max.

My last ride - I will post a screen cap from my Garmin data in a bit - was supposed to be an easy ride, but had a buddy show up and he wanted to have at it a bit.
1:41min - 204W normalized power, 4 short hill efforts of 600W+, 1 hill effort at 890W, multiple 4-500W accelerations.
I ate 10-15 net carbs that day, and the same the day before - and just about every day.

Two rides ago - I went hard to train for an upcoming long mountain ride.
1:30 min - 227W normalized power, multiple short hills and accelerations at 5-750w+
I added one energy bar mid ride just incase of a bonk. Same 10-15 net carb diet.

So thats 61% and 70% of VO2 max efforts at decent amounts of time fueled mostly from fat energy.

MoAlpha

Nice numbers, especially good given the T2DM issue. They imply good aerobic fitness and it's likely the keto diet boosts your fat burning capacity and ability to perform in a fasted state. The numbers on the chart, however, are from exhaled gas measurements, i.e., the amount of CO2 produced relative to O2 absorbed. As you probably know, that's the gold standard and there's no 1-to-1 mapping from that to individual performance.

Steamer

Fat vs. CHO utilization varies wildly from person to person. It's both training and diet related, not just intensity related.

Alan Couzens has lots of real world data on this.

Here are some good reads on this topic from AC:

https://www.alancouzens.com/blog/fatburning_test_2.html
https://www.alancouzens.com/blog/imp..._burning1.html
https://alancouzens.com/blog/improvi..._burning2.html

I think most people would argue that if you are involved in endurance events lasting more than 2-3 hours, it's of great benefit to be as much of a fat burner as possible. Nobody (well, not many people) is saying to not consume CHO on the bike, it's just that keeping up with taking in CHO to compensate for the CHO that is burned can be difficult. And the longer the event, more difficult it is. You can only store so much, and your gut can only process so much.

It all comes down to having a healthy metabolism. If your body can use fat as fuel, it's healthy. Not only does this have athletic performance benefits, but it can prevent T2D, and if you have it, reverse it. T2D is not a permanent condition. Undo what caused it and your body will heal. I should note that having defective aerobic metabolic machinery is starting to be implicated in all sorts of other diseases too - cancer, dementia....

Low carb diet and lots of zone 2 cycling (at or below LT1) is the basic prescription.

MoAlpha

Genetics may be the most important determinant.

Steamer

Anyone can get healthier and better at fat burning, if they manipulate the variables they have control over.