I am not going to cite sources because I am not a pseudo-academic who gets paid for this thing. This is based on a combination of experience, observation, and scientific studies. I would also like to differentiate between chronic low carb diets (like under 75g per day) and carb cycling diets which stagger between low, moderate, and high carb days. I am only speaking of chronic low carb diets.
reduced thyroid function
muscle wasting/inability to build muscle/reduced capacity to recover from exercise
reduced insulin sensitivity
development of food intolerances (due largely to the less mucus production, which makes the gut more permeable).
reduced immune function
diminished or poor body composition (without the use of steroids or "HRT")
reduced overall physical and emotional resilience.
poor gut biome (if not getting sufficient fiber...usually the case because there are pre-biotics in many starchy foods like bananas and sweet potatoes). We ferment some of this into Short chain fatty acids to be used for energy.
HAving said this, I feel obligated to address some caveats and some positives.
The first caveat is that low carbs is relative. If you're a trac and field athlete, and consume 200 grams of carbs a day but also burn 200 grams a day through sprinting/workouts (lets say you consume 200 each day and it goes to muscle glycogen to get depleted again the next day), then you're also eating a low carb diet...but without ANY of the downsides of actually restricting carbs and filling up on excessive quantities of fat. You also get the benefits of improved insulin sensitivity, hormonal profile, lipid profile, and body composition.
Or...you could be a delusion low-carb fad following sheep.
Here's how it works: 1. Fit, athletic, lean people eating well try low carb diets. First see some weight loss. Skin looks tighter (water loss), and you look more aesthetic. Then as time goes on, you begin feeling flat, your recovery diminishes (and with that body comp, immunity, sex drive, etc), and you carb up. You feel good and ralize low carb diets are temporary and not for athletes and laready fit people. you end up eating a chronic moderate carb diet, or you carb cycle and return to being your usual fit, lean, athletic self.
- fat people: Eat low carb. Lose weight. Lose some fat and even more muscle.. Pencil necks and wrists and ankles, with all of their bodyweight concentrated around their center of gravity (midsection...chest/abs/upper thighs). May look decent in clothes but not in a swimsuit.
That's the truth. Keep spinning your wheels or start exercising, eating RIGHT, and having fun.
When I've done it, I've had mostly good experiences.
Some people can become hypothyroid. My hypothyroidism was caused by wheat consumption, so I noticed the opposite. But maybe if I had stayed with it for longer my thyroid function would have eventually taken a beating.
If you don't eat enough organ meats or vegetables there is the possibility of scurvy.
According to Paul Jaminet there can be a down regulation in mucus production leading to dry eyes, dry mouth, and constipation.
Without the prebiotic fiber from starchy roots, the gut bacteria that is in charge of keeping the junctions between cells tight to prevent leaky gut don't get fed, and it can cause dysbiosis and exacerbate leaky gut in some people.
Hematomacrosis (a rare genetic disorder) can happen to people who are prone if they eat a lot of red meat, and don't give blood.
Breastmilk production can be an issue with VLC too, but since your name is Dan, I am guessing that won't be an issue for you.
I did a low carb <30g for a little while, but it just didn't vibe with me. I'm already very lean with no interest in losing weight, so I wasn't in it for that.
I noticed the extra energy, but, it was mostly adrenal / pseudo-energy, and I don't like that. After the experiment, I took my diet in the opposite direction with limiting my adrenaline.
I found it to be too limiting in daily food choice combos. I really like eating lots of starches / fruits / juices all day long.
My main goal for trying it out was to boost my immune system, which, I did get a little bit of for a short while, but, it didn't work out. The key idea there turned out to be watching my arginine intake, supplementing with lysine when I need to, and the biggest key was sleeping better. (And a round of heavy antibiotics.)
I'm not against it for those who have some extra fat on reserves and feel great on the diet with 2-3 meals a day and no blood sugar issues. But, it didn't work well for me. I quickly felt hypoglycemic and had no interest in pushing through that.
I much prefer a diet closer to Japanese foods / PHD / Zone. I found that to make me feel the healthiest / happiest with what I'm eating.
The disadvantages to me of going too low carb is I feel too low energy on it, also I find soluble fiber helpful for well-formed stools and preventing constipation. That being said,I think my current carb intake is fairly low - 1/2 cup starchy veg or rice with each meal, and maybe 1/2 banana or some berries as a snack.
To those that say VLC has no impact on thyroid function I don't believe you. I couldn't figure out for quite awhile as to why my hands and feet were blisteringly cold. I don't have a blood test to prove my theory but my hands and feet go from cold to warm within a short time after I have ingested some carbs. I too was scared of carbs but I train quite hard 3-5 days a week and my body responds unbelievably well to carbs.
I'm not making this about me, but I think it's important to remember there are positives and negatives of every diet.
I'm assuming you've already researched the positives, and perhaps experienced some of them. Paleohacks is full of them. Such as you may, perhaps, feel fuller on low-carb, because you're eating more nutrient dense food.
So, here are some potential negatives:
Yes, it is possible to develop a glucose deficiency on low-carb diets. If this occurs, the body will conserve glucose by reducing T3 and increasing rT3.
The paleo diet, in and of itself, may not cause problems, but if you're undereating, there is potential, no?
What the perfect health diet (Paul Jaminet) calls low carb seems slightly different than other nutritional persons.
Paul estimates that 200 calories of dietary carbs, plus 400 calories from gluconeogenesis, is barely sufficient to prevent a glucose deficiency in a sedentary healthy person.
I think it's also important to note, however, that there are highly variably and individual impacts on mood, brain function, sleep, etc. - from any diet, not just a low-carb one.
I definitely think it's important to consider the role of fungi/protozoal infections versus bacterial ones. Paul Jaminet said in a podcast with Chris Kresser that fungi/protozoa feed on ketones - which can come from eating low carb; or low-carb with coconut oil; or low-carb, coconut oil, and branched chain amino acid supplementation. If you get worse eating low-carb, than that could be an indication of a fungal infection, which is actually not all that uncommon. It takes a while for these infections to show themselves....so that is something to consider. As well, eating too much protein to excess can feed pathogens, which all feed on iron.
Just some points to consider.
My personal experience with VLC was extremely slow recovery times like a hard workout would take 3-5 days to heal. I had constant brain fog, and very poor memory. I added .5 lbs of sweet potato post workout and my stamina, strength, and drive has increased dramatically. Brain fog, poor memory and slow recovery times all disappeared. I am not trying to lose weight as much as I'm trying to gain lean muscle and decrease body fat %. I am still only getting 75-100 grams of carbs a day but it has made all of the difference
For me, I have felt really great for the few days I have been able to sustain it. However, I find it hard to maintain. I will tell myself I am allowed to eat a piece of fruit and next thing I know I have eaten 3 pieces and want to keep going.
For me the upsides were: better sleep habits, less digestive distress.
down sides: very powerful carb cravings and bingeing when I slip off the wagon
I have considered trying again and seeing if I make it through a week if the cravings will go away, but I haven't done that yet.
Moderately low carb diets are beneficial but you don't really have to be zero carb to be considered low carb. If you are just starting out you might find it easier to hang around 100-150g of carbs per day by eating carby vegetables (beets, squash, sweeet potatoes) and some fruit to ease into it.
My personal experience of maintaining low carb eating over the long term is that it was great for about a year, bearing in mind that I had probably a weekly cheat evening (wine, dessert) and kept below 50g the rest of the time. Then I noticed, when I was at my slimmest and strongest and had the kind of body I'd always DREAMED of having, that I was increasingly suffering from three things. I could not sleep and had zero sex drive. And I mean NOTHING. I even deliberately stayed single, even though I looked how I'd always wanted to look, because who wants a girlfriend who isn't interested in having sex? And what's the point in working your arse off to look good if you then inflict celibacy upon yourself? None of this was a problem when I was less slim, less strong, less fit and 'overweight'.
I think now I've found a better balance, although unfortunately I've had to kiss goodbye to that magazine cover body. I'm softer now, though still fit, and I believe healthier. But I still look good by the standards of your average person on the street, I can SLEEP - which is just the most wonderful feeling ever, as anyone who's suffered from insomnia will fully understand - and my sex drive has returned to normal.
I don't know if it was the low carbs or merely the fact that my body was under a lot of stress and may not have had enough bodyfat (which I could equally have achieved with a high carb, low calorie vegan diet) for it to be happy. Honestly, though? My gut feeling is that it needed more carbs. I feel this very strongly and have no hard evidence for it whatsoever :)
Oh my, it's just horrible! So dangerous--if you try it, you might suffer the following:
Serious weight loss (65 lbs for me)
Low HbA1c and normalized blood glucose levels
Loss of GERD symptoms
Decreased insulin and testosterone levels (in women)
Menses regularity--may lead to pregnancy in otherwise annovulatory women
Loss of acne, hair stops falling out.
Cessation of asthma
Sudden drop in triglycerides and increase in HDL
Fatty liver reversal
So very bad for you. I wouldn't try it if I were you.
Interestingly evelyn lists 11 reasons low carb is a fail too:
Which includes brain fog, insomnia, extreme LDL levels and increased inflammation.
Carb reduction is invaluable for controlling diabetes, and can be useful as a weight loss technique if it results in reduced food consumption overall.
I haven't found many, personally. Not in my vlc/keto experience or in all my reading on the subject.
On the contrary. I have more clarity of mind, consistent energy and better digestion.
Sure, a few downsides:
I do miss my taters, sometimes... Until I eat some and remember how much carbs bloat me.
Keto-breath. Though that seems to go away after some time.
I am never hungry before noon, so it makes brunch dates with friends a bit challenging.
Jimmy Moore says it's the ONLY way to go, and anyone who says otherwise is a "hater". Who can argue with that logic?