Part of the allure of the Primal eating plan is that it’s effortless. There’s no calorie counting, no stressing over macronutrient intakes – eating PB simply means choosing to eat real, whole foods that man has been eating for tens of thousands of years. You can go higher carb or lower carb (I initially recommend low carb, just because it makes losing weight and stabilizing your metabolism incredibly easy, especially for folks coming off the SAD), and as long as you’re eating real foods you’ll be getting healthier and losing body fat.
This isn’t enough for everyone, though. To go back to yesterday’s “hormones as software” analogy , some people are hackers who relish digging deep into the fine print of software manuals discussing human nutrition and hormonal responses. Others – the bulk of my readership – are cool with using their standard-issue, factory Mac or PC to reap the basic benefits of Primal living, while others prefer learning Unix and taking night classes in comp sci down at the local community college after work. They’re the ones who spend the time to fiddle with the programming language of our bodies in order to become real hormonal hackers. I get that. I love that stuff, too, if only to able to take the information and distill it for a large audience. Though one can see tremendous results with minimal effort following the simple principles of the Primal Blueprint  (i.e. how I approach my own eating habits and how I recommend others do as well) digging deeper into the science of leptin and how carb refeeds impact leptin levels can unlock an entirely new level of fat loss (and understanding of why that fat loss is occurring).
All this leptin and carb refeeding stuff was prompted by reader questions; I get a fair amount of questions about carb refeeds, and, because the PB is a moderate to low-carb plan, people (understandably so) tend to assume that carbohydrate refeeding contradicts its basic tenets. They make an incorrect assumption.
As mentioned earlier, the Primal Blueprint is the simplest, most enjoyable, most sustainable way to normalize your weight, a description borne out by my own experiences and the experiences of my readers. If you don’t want to fret over every last macronutrient as you lose weight steadily, a low carb, high fat, moderate protein Primal eating plan will do the trick. That said, I am not overly concerned with getting folks to 6% body fat , nor am I interested in producing champion body builders. I have nothing against getting as lean as possible; it’s just not my focus. Turning the Primal Blueprint  into a super-leaning out program would mean changing its inherent nature as an effortless system without weighing and measuring. You see, I’m concerned with helping people reach their natural genetic potential through sustainable lifestyle behaviors. And for most people, their natural genetic potential is pretty damn good – lean, strong, fit, healthy. Very few people can achieve that ultra-ripped, Men’s Health cover model look without significant, painstaking adherence to a strictly regimented program.
Carb loading or carb refeeds can be used, quite effectively, by those interested in dropping the last couple body fat percentage points. I wouldn’t recommend it for overweight individuals. For them, sticking with a low carb, Primal eating plan is the easiest, safest way to drop the pounds. And you can do it with Primal foods .
The purpose, as I see it, of carb refeeds is the restoration of leptin levels in the dieter. As we know, caloric restriction reduces leptin levels. With lower leptin comes increased hunger and reduced adherence to a diet. Cravings  arise. Energy wanes, immunity suffers. The lack of leptin elicits the cascade of hormones that down regulate metabolism and energy expenditure. Your muscles use less energy and become more efficient – but weaker and less effective. Menstruation and fertility  become issues. Dropping calories even more just makes the problem worse. You need to restore leptin, at least for a bit, to right the path. A carb refeed can help you achieve this.
Who needs to refeed? No one “needs” a carb refeed, especially if he or she is feeling good, looking good, and continuing to lose weight with plenty of energy. I never consciously stuff myself with carbs, and I’m doing okay. Remember, too, that a low-carb eating plan doesn’t equal a low calorie eating plan. If your weight loss has stalled, however, and hunger is a constant issue, no matter the depths of your caloric restriction, it may be wise to consider a periodic carbohydrate refeed. If you lack energy throughout the day and your immune system is suffering, you might need to restore your leptin levels with a carb refeed.
Here’s the quick and dirty Primal way to do it:
On your heaviest training days (heavy lifting, sprinting, anything that results in glycogen depletion), increase your carbohydrates and limit your fat intake. Yes, limit your fat  intake to around 50g (eyeball it – don’t demolish that stick of butter today). Don’t cut it out altogether, mind you, but emphasize carbs over fat. Fat doesn’t have much of a short-term effect on leptin , and, since we want to increase leptin in the short-term without gorging on overall calories , limiting fat and emphasizing carbohydrate is the way to go. Don’t do much to your protein intake. Just keep it relatively normal. Limit your refeeds to once, maybe twice a week, and always after really big workouts, but really go for it. Eat a lot of yams, sweet potatoes, fruit, plantains, squash – any Primal source of starchy carb will do the trick (grains and legumes are still problematic, so keep away). Eat more total calories than you’d normally eat and way more carbohydrate calories than you’d normally eat – at least 250 g-300 g worth. Finish your refeed day with a decent chunk of lean protein (chicken breast, cottage cheese).
You’ll probably get that bloated, water-weight feeling the following day, especially if your diet is relatively low-carb, but that will go away after a day or so. Leptin will rise (independent of fat storage), glycogen  will replenish, and your appetite will normalize. Since you’re already fairly lean with low circulating leptin (and, remember: you should be relatively lean before employing refeeds), your leptin sensitivity will be high. The leptin bounce won’t be enough to dull your leptin receptors; that generally only happens with the obese, who have chronically elevated leptin.
There are other methods. Some experts recommend two or three day-long carb binges. Others say a week long refeed works best. I don’t know about you, but that seems like too much work. I honestly can’t see myself giving up pastured butter and ribeyes for a week straight. Starch without fat gets real old, real fast.
I may not find refeeds necessary for my goals, but I recognize that they can help people reach their goals. Everyone’s different. I can’t guarantee my way will work – you may have to get super strict and follow Martin Berkhan’s or Lyle McDonald’s methods to reach your desired level of leanness. Still, the Primal refeed is worth experimenting with, especially if you’ve reached a plateau  lasting a month or more. I’m a big fan of steady, gradual weight loss, and the leaner you get the slower it gets, but it’s not for everyone. The above recommendations simply represent a way you can adhere to the Primal eating plan  and still tinker with carb refeeds without overly disrupting your usual diet.
If you’re still having trouble reconciling the refeed notion with your idea of Grok’s lifestyle, just imagine you found a bushel of mangos, or happened upon a particularly fruitful trove of edible roots. You think Grok would have tossed those mangos to avoid the carbohydrates?
Let me know how it works out for you!