This is an old thread, but thought I'd pop back in to let you all know how Paleo is going for me.

I went off Paleo for almost the entire summer, ate like a crazy carb addict, and gained back a few pounds. Then I went Paleo again and lost it all in a few weeks. Funny how those carbs really cause water retention.

Having gone Paleo-back to SAD-back to Paleo, I can tell you this: Paleo eating really does make me FEEL better. Regardless of the number on the scale, I feel less energy fluctuations (i.e. no blood sugar rushes/drops) when I eat Paleo, and overall I feel quicker and lighter. I do get terrible carb flu initially, though, so I have to battle through the first few days.

Good luck everyone!

Have you tired to cut down the size of your meals?

Funny, because I observed the opposite... Or maybe you were dehydrated at the beginning, and the water from fruits and vegs got just trapped in your body because of the salt from other products?

Actually your experience seems to be in the minority. Most people find that their body holds more water on a high-carb diet than a low-carb one. This is because carb digestion requires more water, so the body holds onto more (because the body needs it).

This phenomenon is so often mentioned on low-carb boards and in low-carb books, that I had assumed it was universal. It's interesting to hear from someone who experiences the opposite. I do wonder whether in your case you eat a higher sodium diet when eating low-carb. For example, in my own case, the only time I retain water on low-carb is when I've overindulged in high-sodium protein sources like jerky or deli meats.

In my case, there's about a 5 to 8 lb difference between "clean" (low sodium, whole food) low-carb and clean high-carb. I don't worry about that difference, because I know it's just the water differential required for digestion.

I don't think that 5 to 8 lbs matters in itself, because it's fat loss I'm concerned with, not water. I just have to remember when switching from low-carb to higher-carb or vice versa that I can expect to see that difference.

Likewise, when I switch to low-carb, I have to be aware that that rapid drop of 5 lbs is "just water." That matters, because if I have a high-carb day, I'm going to see those 5 lbs again, and if I don't realize it's just the normal water-ratio of the two plans, I can assume that low-carb eating has some kind of magic weight loss effect compared to higher-carb eating.

I CAN eat a little more on low-carb to lose the same amount of weight as on a higher-carb plan, but it's not as big a difference as that first week can make it seem (again because of the water differential between the two plans).

Thank you very much for your explanation, I didn't know that. And is the source of this water retention on hi-carb fruit/vegs diet known? Salt is surely not the case for me, I'm on 95% RV + eggs and sushi. And every time I eat some fruits, it makes go to the toilet, so the water in my body doesn't rise.

Apparently the mechanism by which digestion needs more water for carbs is well-understood, because it's often explained in very technical terms in some of the low-carb books. Personally, I'm not much of a precision learner (which is why I transferred out of nursing and into psychology), so that everything I learned in college and graduate school chemistry and biology, I've forgotten (if it was ever retained after semester was over).

So while I have a vague understanding of why carbohydrate ingestion requires more water, I couldn't explain it to save my life. I can't think of a book title that I could guarantee explains the biochemical process, but I suspect Gary Taube's book "Good Calories, Bad Calories," might.

If I run across anthing, I'll post a link.


As for fruit, there's probably another explanation there. Some folks are very sensitive to fruit sugars, which can cause diarrhea (and therefore water loss, even to the point of dehydration).

This isn't universal. Some people are sensitive to all fruits, and others are sensitive to only some. In my case, I'm sensitive to some and not others.


I digest apple and citrus very well (no unusual bathroom habits), but if I eat more than one small pear or plum, yikes it gives me an idea of what dysentery must feel like.


I've read that in some cases, these effects are temporary and a result of exposure. The more often you eat a particular fruit, the less severe effects will be over time. I've noticed this to some small degree with Ranier and Queen Anne Cherries (yellow cherries with a red blush).

Every season (usually three to four weeks) around mid-July, I eat tons of these cherries and suffer for it (I don't leave the house, because I know I'm going to eat enough to make me slightly sick).

At the end of the season, I can tolerate the cherries better than at the beginning AND each year I seem to be able to eat more without ill effect.

I will offer my recent experiences. I did low carb last year, and lost 20 lbs, then started eating SAD again. I recently began the Primal Blueprint diet and in a week have lost 5 lbs which I assume is water weight. But I do feel better, and less bloated, which I really like. And my energy is more linear now, instead of crazy highs and lows. So even without having read the research (which I did) I would have to say low carb works better for me overall.

In my case I wouldn't call it a diarrhea, it's just like sort of synchronizing urinating about 15 to 30 minutes after eating 1-2 lbs of fruits.

Well yeah, that's not a digestive issue, that's just all the water in the 1-2 lbs of fruit. I don't usually eat fruits and vegetables in large enough portions to notice a significant difference in urinary output (except for watermelon).


I'm pretty carb-sensitive, and carby foods tend to trigger hunger and cravings, so I tend to eat fruit in smaller portions and paired with aother foods (and never on an empty stomach in the morning - that makes me almost as neauseous as eating more refined sweets for breakfast - which I absolutely can't do without getting sick).

I try to make sure that in all my snacks and meals that I'm getting more calories from protein and fat than from the net carbs.

Fruit doesn't trigger the cravings/hunger as much as refined carbs do, but even so, I have to watch portions, not only because of the hunger triggering, but because I have irritable bowel issues, which compounds the issues fruits and vegetables can cause anyone who suddenly eats more than they're accustomed to. Most folks can prevent the issues by gradually increasing freggie intake, and that's true for many folks with IBS too, we just have to do the gradual-increases at in slower, smaller increments.

I find it absolutely fascinating that there's so much variation in reaction to foods. It makes me wonder why (until very recently) the research in the field of weight loss has been looking for "the diet" that is most effective (for everyone, by implication). It seems to me that it's been obvious for decades that there's such variability, so it's been a surprise to me that the research community is now only looking into what accounts for the dfferences, rather than just trying to find the single, best plan that would work for the majority (if not everyone).