The FastDay Forum

http://evidencebasedfitness.blogspot.ca ... h-you.html has an opinion.

Not got to the full study yet, but the above points to the usual tiny difference in REE measurements and also notes that after the second weight loss phase (33% calorie restriction) the statistical significance of FFM had gone away.

[carorees]

Oh well...

More on protein intake fro mark and his daily apple, last week:
http://www.marksdailyapple.com/how-much ... more-36135

http://evidencebasedfitness.blogspot.ca ... h-you.html has an opinion.

Yes, quite a high opinion of himself, and a bit of an attitude too. And his view that unless you have read the real paper you shouldn't talk about it closes down discussion a bit!

Still, the weight of opinion seems to be in favour of keeping up protein intake on fast days (or when dieting generally) to at least 0.8g / kg - this study shows it, Mark states it (thanks for the link skippy), and Dr M has said it too I think.

Is there any counter-evidence? If we go lower and risk loss of FFM (bad, presumably) do we also encourage autophagy (good, presumably)?

Can't access the full paper, but work from the same group published late last year worked on the same ground - high vs normal protein at 33% of calorie requirements for an extended period.

"This resulted in the following macronutrient compositions during the weight loss period of time when 33% of the original energy requirement was provided: protein/carbohydrate/fat of 60/5/35 En% for HPLC, of 60/35/5 En% for HPNC"

60% protein means you're living on chicken, tuna, turkey etc possibly supplemented with protein powder shakes and the like.

As the trial was one of continuous low calorie intake (one third of TDEE) for three months followed by a further 9 months restricted calorie intake (intake of two thirds of TDEE ie one third restriction) I don't believe it offers evidence for what to do on 5:2 fasting protocols especially when we have some trial evidence pointing to the same preservation of lean body mass and REE in ADF protocols.

Is there any counter-evidence? If we go lower and risk loss of FFM (bad, presumably) do we also encourage autophagy (good, presumably)?

http://www.ncbi.nlm.nih.gov/pmc/article ... /table/T2/ lost less than 1 kg of FFM on average, with 20% protein on modified ADF with 20-30% of TDEE on fast days. This study had reductions in both systolic and diastolic BP. (Not sure I've seen this one before). Impedance analysis of body composition.

http://ajcn.nutrition.org/content/81/1/69.long is true ADF (zero calories hence zero protein alternate days) and showed a loss of FFM by DEXA of 0.6 kg.

"FFM decreased slightly in all diet groups, without differences between diets" according to the group which published the paper in the OP, in a separate paper at http://www.ncbi.nlm.nih.gov/pubmed/22935440. Isotope dilution used for body composition - FFM was calculated by dividing total body water by the hydrating factor 0.73.

A short period of true ADF with no significant weight loss or body composition change reported at http://jap.physiology.org/content/99/6/ ... nsion.html using DEXA showed a ~1 kg reduction in mean FFM

Varady's modified ADF uses <30g protein per day on "fast" days http://ajcn.nutrition.org/content/90/5/ ... nsion.html which resulted in " Fat mass decreased (P < 0.01) by 5.4 ± 0.8 kg after 8 wk of diet, whereas changes in fat-free mass were not significant (−0.1 ± 0.1 kg) " using impedance measurement.

Similarly Varady reports "fat mass decreased by (P<0.0001) 5.4±1.5 kg and 4.2±0.6 kg, while fat-free mass remained unchanged (ADF–HF: 1.1±1.3 kg; ADF–LF: 0.5±0.7 kg)." in modified ADF 25/125 % of TDEE at two fat levels. DEXA analysis. http://www.ncbi.nlm.nih.gov/pubmed/23612508

While I agree that high protein (up to 35% of dietary intake) is beneficial to fat loss in prolonged calorie reduction my opinion is that the ADF trials do not provide an evidence base for its use and I fall back to the Horizon documentary and "go go mode" and all that where eating less protein was a key part of the argument for better health outcomes.

Of the published trials of IF only Harvie's 2-day low carb diet uses more protein, around 50g per day on restricted days.

Bumping my first thread (posted a little over a year ago) because I found a few links searching for an answer to a question I posed in this thread:

I see some numbers floating around that don't seem to add up here, regarding a low-carb, low/moderate-protein, high-fat diet. Considering myself at my target weight (~82kg) my TDEE will come in ~2400kcal/day.

The 0.8g/kg thumbrule for protein (to reduce cancer risk deriving from excess protein consumption) means ~66g of protein per day, or 264kcal/day.

I've seen carb recommendations of about 100g/day limit, or about 400kcal/day. We're up to 664kcal.

That leaves 1736kcal (193g) to be found in fat, which would be 72% of my daily calories.

A thoughtful response from @carorees referred me to some daily diet examples from Peter Attia, who indeed achieved the ~70% fat number, but his protein was more than double the recommended amount, coming in at 1.67g/kg. carorees said it was probably okay for him because of how much he exercised.

So I found a couple of websites that look like they at least attempt to answer the question, the first one answers a question from someone who is obviously taking too much protein, a whopping 4.4g/kg:

There is no evidence that consuming 0.8-3.6 g/kg/day of protein is associated with any adverse effects for healthy, active adult men and women. The Acceptable Macronutrient Distribution Range for adults 18 yr and older is 10%-35% of total calories. The recommendations for endurance athletes are 1.2 to 1.4 g/kg/day and for strength athletes, 1.2-1.7 g/kg/day.

At two grams of protein per pound of body weight, you would be consuming 4.4 g/kg body weight per day. Extra dietary protein must be broken down in the body, which increases formation and excretion of the nitrogen waste product urea. This additional waste increases fluid requirements and places a considerable load on the liver and kidneys. In some individuals, high protein intake can cause hypertension, increased fluid needs, diarrhea, abdominal cramps, and/or an imbalance of the essential amino acids.

This advice, if true of course, is very helpful and gives some context to the "0.8 g/kg/day" standard recommendation. A second site has a lot more detail on what happens when you get too much protein:

To determine how much protein you actually should be getting, you need to be familiar with a term called “nitrogen balance”.

Here’s how nitrogen balance works:

Nitrogen enters your body when you consume protein from food or amino acid supplements, and nitrogen exits your body in your urine as ammonia, urea, and uric acid (all the breakdown products of protein) When the amount of protein you eat matches the amount of you use, you’re in nitrogen balance (3).

As you can probably deduce, if you don’t eat enough protein, you’ll be in negative nitrogen balance and quite unlikely to be able to repair muscle after a workout (a “catabolic” state). If you consume too much protein, you’ll be in positive nitrogen balance, and while you’ll definitely have what you need for muscle repair (an “anabolic” state), there can be some health issues that arise when you achieve too positive a state of nitrogen balance. This is because your body gets overfilled with ammonia, urea and uric acid, which have some nasty side-effects we’ll get into that in just a bit (32).

The current US recommended dietary allowance (RDA) is 0.36 grams of protein per pound of body weight per day (0.8g/kg), and was designed for most people to be in nitrogen balance – without protein deficits or protein excess. While athletes and frequently exercising individuals need more protein than this, you’ll frequently see bodybuilders, football players, weightlifters and other big strength and power athletes taking this to the extreme and consuming far in excess of this protein RDA (in some cases up to 2 grams per pound!)

But studies suggest that even for athletes, there really isn’t much additional benefit of exceeding 0.55 grams per pound of protein (1.2g/kg) if you want to maintain nitrogen balance (23). If you’re trying to exceed nitrogen balance for the purpose of putting on muscle or recovering from more extreme exercise sessions, studies also indicate that you don’t need to eat more than 25% above that 0.55 g/lb, which would be 0.55×1.25, which is 0.68 g/lb, or 1.5g/kg. For simplicity, I prefer to just round that up to 0.7 g/lb (35).

I'm guessing, and I hope there are those out there that know more definitively, that the increased cancer risk associated with going above 0.8g/kg/day protein intake is relevant to mostly-sedentary people, and that in general what causes all of the non-cancer stuff listed above, over time, is what increases cancer risk as these effects and toxins accumulate.

One quote from the second link I find useful to this discussion as well:

This brings me to my next point. What are the actual risks of eating excess protein, or having your nitrogen balance too great?

First, consider that ammonia is a toxic compound to the body. Once you get close to about 1000 calories a day of protein (that’s about 250 grams), you can no longer convert ammonia to urea, and you begin to build up this toxin within your body. This is extremely stressful on your internal organs, especially your kidneys.

Next, excess protein can cause dehydration if you do not drink enough water. This is because your kidneys need more water to convert ammonia into urea.

Finally, mammalian target of rapamycin (mTOR) is a gene in your body that is directly correlated to accelerated aging. Decreased activity in this gene can be caused by moderate caloric restrictions and slightly lower amino acid intake (14). So excessive protein intake and a constantly positive nitrogen balance could actually shorten your life!

So the take-away message is this: eat as much protein as your body needs for repair and recovery (about 0.55g/lb) eat a little more if you want to put on muscle (up to 0.7g/lb), and then take in the rest of your calories from healthy fats and vegetables, with limited amounts of fruits and safe starches for fueling intense bouts of physical activity.

[Tracieknits]

Every time my husband posts about anything remotely related to low carb, I cringe. I am very relieved to see Carorees' post above that too much low-carb is potentially dangerous and unhealthy. I will add that to my nagging of "if you want to eat low carb, you'll need to learn to cook and shop."

I agree completely with the sentiment of "moderation in all things, including moderation."

I aim to fill at least half our plate with veggies at every meal. I try to relegate the rest of the plate's real estate in equal parts to protein and healthier carbs (brown rice, potatoes with their skin, beans, etc). To be honest, that's about as precise as @BruceE's meals are going to get until he learns how to cook for the family

How much muscle you lose while dieting has a great deal to do with how much protein you eat while dieting. Low fat diets were notorious for causing muscle loss as they were often very low in protein. Low carb diets pretty much spare muscle. A 500 calorie modified fast twice a week with 4-6 ounces of protein a day combined with a diet that includes sufficient protein on the other days of the week should not result in significant muscle loss.

The problem with diet-induced muscle loss is that one of the primary muscles that gets reduced is the heart. Other organ-related muscles also are affected. Not a good idea!

[carorees]

Carorees,

How much muscle you lose while dieting has a great deal to do with how much protein you eat while dieting. Low fat diets were notorious for causing muscle loss as they were often very low in protein. Low carb diets pretty much spare muscle. A 500 calorie modified fast twice a week with 4-6 ounces of protein a day combined with a diet that includes sufficient protein on the other days of the week should not result in significant muscle loss.

The problem with diet-induced muscle loss is that one of the primary muscles that gets reduced is the heart. Other organ-related muscles also are affected. Not a good idea!

That's great info, thanks @peebles! Can you send me PubMed links to the studies on this? I'm creating a 'library' of useful references so these would be great!

This raises some interesting questions:
How much muscle loss is 'acceptable' due to the aforementioned decrease in weight? I presume some loss of cardiac muscle would also be simply due to less weight (i.e. reversal of obesity-related cardiomyopathy from the weight loss)?
How much can weight training prevent muscle loss during dieting (especially in the light of your comments about non-skeletal muscle loss)?
How much protein should one eat and how does this square with the need to reduce protein in order to keep IGF-1 levels down? (i.e. how much protein is sufficient protein?)
Varady's studies into ADF in humans suggests preservation of FFM but the published studies are quite short in duration. Does the rise in GH with fasting spare muscle in the long term? (studies into the metabolic changes that occur with fasting show that most are due to the lack of carbs while fasting so it's perhaps reasonable to assume that both low carb and fasting results in preservation of muscle)

Perhaps I should move this discussion to a different thread?!!

The data about sparing muscle loss with sufficient protein comes from various studies of ketogenic low carb diets with sufficient protein. I don't have the references handy as this is something I have read repeatedly over the years whenever serious discussions of low carb diets are held, but I suspect you could find them with a Google Scholar search. Typically low fat dieters also limit protein since they are phobic about meat, cheese and eggs, and lose more muscle than the low carb dieters who tend to if anythign overdo protein.

The numbers I've found on various web sites that discuss how much protein is ideal give these numbers: You need .8 grams of protein per kilogram of total body weight to provide protein for muscle repair for a person who is sedentary, .85 grams for a person who exercises lightly, and .9 grams for someone who exercises at moderate intensity. However, moderate intensity is more intensity than most of us get from an hour visit to the gym a few times a week. Most people overestimate their activity level. If you work on your feet and run around all day you can consider that moderate intensity. Otherwise, "light" is probably a better choice.

But if your carbohydrate intake is low enough to put you into a ketogenic state for a longer period than three days it typically takes to burn through your glycogen, you would need to eat extra protein to supply the extra glucose your brain requires. (Protein grams convert to glucose grams at a rate of about 58% thanks to a clever trick your liver can perform.)

With a 5:2 diet where you are not eating low carb on the other days of the week, you probably don't need extra protein because you would be burning glycogen stored in muscles and liver on your fast day and don't need to convert protein to glucose. So that .8 to .85 g of protein per kg of weight should be sufficient.

There is no advantage in over-consuming protein, however, and low carb dieters who misunderstand the diet and live on huge servings of meat tend to develop the dreadful bad breath that gives Atkins diets a bad name, not, as they are told not just because of the ketones they create but because excess breakdown of protein releases ammonia compounds.

I haven't researched IGF and it's relationship to either fasting or protein yet. But after dipping my toe into the research about intermittent fasting and intermittent caloric restriction, I'm starting to think that the data just isn't there to draw any conclusions for humans doing a 5:2 type diet.

Most of the research cited is for multi-day long stints of pure fasting and most of that research was done in rodents. Rodents are a terrible model for human dietary research given that they have very differently functioning pancreases from humans and are adapted over millions of years to entirely different diurnal patterns of eating and entirely different kinds of foodstuffs than humans are.

I'm finding this alternate calorie restriction approach fascinating, but there is so very little actual research on it save for those Varady studies that you mention that I would withhold judgment. It took a decade after Low Carb dieting became popular for high quality research to emerge which studied more than a handful of people. Much of the early Low Carb research was very misleading because the studies were so short and involved so few people--and because, too, the people doing the research had personal reasons for achieving certain results. The larger, longer epidemiological studies pretty much confirmed what those in the online low carb community had observed over the years. Much less dramatic than the claims of the people writing the bestselling books, but still positive and useful.

Meanwhile, boards like this where people report their actual experience with the diet are where you will learn the most about what real people's experiences with any diet are long-term, though of course, the population here is self-selected to be people who are successful with the diet. You need the big epidemiological studies to see what the experiences are of the people who don't do well on it and to tease out why.

But after having put quite a lot of time into reading nutritional studies (mostly in regard to ketogenic low carb dieting) I don't have much respect for most nutritional research because the quality, when you look at the actual studies, can be so dreadful, the statistics so poorly applied, and the motivations so tainted by sponsors selling some product or other.