Week Three of the Keto Reboot: Why It Feels Awful, Cheat Days, and "Starvation Mode"

2020-01-22

In this recording

A 112-minute Live from January 22, 2020, broadcast away from home. It's a weekly Q&A: I scrolled back through every post in the Keto Basic group that week and answered them in order. The group had started a reboot on December 1, so most people were somewhere in weeks three to eight. I've left out the names of the members whose posts and comments I read, and the personal details some of them shared.

• [1:56] Who I am: basically a research assistant and a high school science teacher. I didn't do these studies or invent ketosis; I read a lot of them, and I'm limited on medical advice.
• [4:19] A member had sushi off plan. Compared with fried rice or a sugary sauce over white rice, a few pieces of sushi with fish, cucumber and avocado is probably low carb, if not keto. One meal is under 5% of your food decisions for the week.
• [6:55] My glycogen math: about 700 g stored on a standard diet, against under 20 g of carbs a day on keto. One 100–150 g day can't refill that, especially at a calorie deficit.
• [8:04] What a high-carb day does do: the gut bacteria used to 20 g a day suddenly get seven times as much, which is where the gas and bathroom trouble come from. One reason some people run 50–60 g in maintenance, though more carbs can bring cravings back if you're still insulin resistant.
• [11:00] One meal a day (OMAD), or time-restricted eating. It limits how much fits in one sitting, and it turns snacking into a yes/no rule. People are good at yes/no and bad at "only so far", like the difference between speeding and running stop signs.
• [14:44] Members' plain dinner photos, not food-blog plating. That's what the keto community is missing: what a normal plate of on-plan food looks like.
• [19:16] A member's plate of chicken breast, brussels sprouts and two slices of bacon: about 462 calories, 65 g protein, 12 g fat, 10 g carbs. Nearly 6 to 1 protein to fat, because chicken breast is about 10 to 1 and bacon about 1 to 1.
• [20:36] Two of those plates would cover my protein (about 130 g) for under 1,000 calories, when I burn 2,000 to 2,500. That gap is about 2 pounds a week.
• [32:13] Low-carb drinks. A keto coffee company had sent me a case of free product to review; I said it was good.
• [33:33] My own reboot: I went off plan over Christmas, New Year's and my birthday, restarted around January 7, so on the day of this Live I was in that awful week two or three myself.
• [34:21] Why weeks two and three are the worst: you can make ketones in two or three days, but I said you don't use them well until about day 12 at the earliest, more often days 17–21, for some people 28–35. In between you get the restriction and the side effects (keto breath, smelly sweat, a possible keto rash, losing sodium and potassium) without the payoff.
• [37:17] If you have those symptoms in weeks two and three, it's probably because you're doing it right.
• [38:37] What comes after: by weeks five to seven, much less hunger, half the steak you used to eat, and no late-night kitchen cruising.
• [39:09] My Paris line: you can't get to Paris without the long flight.
• [41:07] Hunger is hard to measure; it's tied to insulin, ghrelin and leptin, and it seems to go wrong with insulin problems.
• [42:29] Members who shared blood pressure, cholesterol or A1C numbers all reported improvements, but I said it could be confirmation bias, and that any intentional diet beats no attention at all.
• [43:49] The worst critics can say is that keto doesn't beat other diets. Most diets work if you stay on them.
• [45:41] Direction matters more than speed: leaving 30 minutes earlier beats speeding for three hours.
• [48:38] "Why do you do it?" Most group answers were "for me", not for family. I said intrinsic motivation predicts success better than extrinsic, and learning to do it for yourself is how a diet turns into a way of eating.
• [56:26] Being heavy felt like the luck of the draw to me. I was a four-season athlete and still got heavy, drinking a lot of Coca-Cola. Fixing a broken hunger gauge is what gave me agency.
• [59:22] "I'm not seeing movement on the scale" from someone who started January 1: right on schedule. Expect a first-week water drop, then little until ketones are in use. During the introduction phase I don't push calories.
• [1:01:48] My theme for 2020: separate energy from nutrients. Starvation (no fat left) is different from nutrient deficiency (scurvy, rickets). A person with fat on board isn't short of energy, but can still be short of nutrients.
• [1:04:28] Starvation mode and adaptive thermogenesis. I said running colder is worth only about 100 calories a day, that fidgeting falls when energy is short, and that both reverse once ketosis gives you access to fat.
• [1:06:22] Gluconeogenesis works on demand, not supply: drinking protein shakes doesn't make your body turn it all into sugar.
• [1:09:18] A ketone drink before you're adapted is expensive pee.
• [1:12:49] A member in maintenance binged on pizza. Back on the horse, fiber, a walk. Make decisions, not mistakes. No healthy diet includes cake daily; treats are treats.
• [1:16:17] Cheat days. A carb cheat at controlled calories: some stomach upset, back in ketosis fast. A calorie cheat on keto foods after six days at a 500-calorie deficit: you're still down about 2,000 for the week.
• [1:17:53] The all-out cheat day (pizza, beer, wings) can be big enough to refill glycogen, about 2,800 calories, and set you back three or four days. Do that weekly and the diet stops working.
• [1:20:49] Holidays and birthdays: take up to 60 days a year, eat what the family eats, and give me the other 305.
• [1:22:57] Does 200 g of carbs take longer to clear than 50 g? I said yes, about four times as long, since the sugar gets burned first. The longer you go without ketones, the more of your cells stop using them.
• [1:26:11] Whole fruit comes with fiber, which blunts the blood sugar response. A little fruit can be a fine way to spend your carb budget.
• [1:27:04] A member craving Doritos without being hungry. That's wanting a sensation, not food. Take a handful and walk away from the bag.
• [1:30:00] When snacking shows up, I ask about sleep and stress, since snacking is often self-comfort.
• [1:32:24] Mug cakes and keto-fied desserts are still dessert: high calorie, low nutrition. Better than the sugary version, but a dessert is still dessert.
• [1:36:25] A member's fasting ketones fell while glucose rose. A blood test is only a peek at what's in transit; 0.5–5 mmol/L is the range I gave for nutritional ketosis. A higher number doesn't show how many ketones you make or use.
• [1:38:33] Fasting: fine to try, but cover calcium, potassium and iron.
• [1:41:29] Tracking apps: the group liked Carb Manager, which I hadn't tried yet. I'd gone off MyFitnessPal. These days I track mostly to build meal plans for other people.
• [1:44:43] A pitch for my paid one-year coaching, then a sign-off asking for likes and shares.

Watching this in 2026

The best part of this Live is the honesty about weeks two and three. People quit right when the diet is about to get easier, and "the symptoms mean you're doing it" is still the most useful thing I can tell them. The yes/no rule for snacking, "take 60 days, give me 305," and checking sleep and stress before blaming willpower all hold up too.

Some things I'd say differently now:

• The day counts for adaptation (day 12, days 17–21, up to 35) were my rule of thumb, not a measured timeline. Studies of long fasts found the brain shifting to ketones as its main fuel after weeks (Owen et al., 1967), so "weeks, not days" holds. The exact numbers don't.
• Starvation mode. I said ketosis reverses the metabolic slowdown, and that it only really happens on high-carb, low-calorie diets. The evidence pages I use don't back that. In a ward study, 17 men switched to keto at the same calories burned only about 57 kcal a day more, and body-fat loss slowed after the switch (Hall et al., 2016). In another, carb restriction lost less body fat per day than fat restriction at the same calories (Hall et al., 2015). Keto doesn't switch off your body's response to eating less. What it can do is make eating less easier.
• "At least as good as any other diet." That one holds. Over 12 months, healthy low-carb and healthy low-fat came out close (−6.0 kg vs −5.3 kg, not significantly different, DIETFITS). Across 13 trials of a year or more, very-low-carb ketogenic diets lost slightly more, under 1 kg (Bueno et al., 2013). Pick the one you'll stay on.
• "Four times as long" to clear 200 g vs 50 g of carbs is the sugar-cube version of the math. It ignores how much of that refills glycogen and how active you are. The direction is right: a bigger carb load takes longer to clear.
• Fasting and cancer. I mentioned autophagy and cancer in passing. That isn't on the evidence pages I use, so I'm not repeating it here.
• The members' blood work. I said myself it could be confirmation bias. If you take diabetes or blood pressure medicine, talk to your doctor before cutting carbs hard. Cutting carbohydrate has the most evidence for improving blood sugar (ADA, Evert et al., 2019), so doses can need changing.
• The free product and the coaching pitch. I said on air that the coffee was sent free, which is better than not saying it. I still wouldn't review gifted products in a nutrition Live now, and I wouldn't end a free Q&A with a sales pitch and "nobody has failed."

Who should be careful

The 1,000-calorie example at [20:36] was my own math for a 6-foot, active man, not a target for anyone else. If you have a history of an eating disorder, go through your doctor or therapist before cutting, fasting or doing OMAD.

Key points

• Weeks two and three are the hard part: ketones are being made but not used well yet, so you get the side effects without the benefits.
• One off-plan meal is a small share of your week. Get back on at the next meal.
• Lean proteins like chicken breast and white fish make big plates at low calories. Bacon, eggs and cheese run about 1 to 1.
• An all-out cheat day can cost several days; a celebration meal a few dozen times a year is fine.
• Keto doesn't beat the metabolic response to eating less (Hall 2016); it can make eating less easier.

Related

• Guide: fat adaptation · the first weeks · stall vs fluctuation · blood meters · energy balance · medications · eating disorders
• Blog: the week-three stall · what happens if you cheat · metabolic advantage? · Kevin Hall's ward studies · DIETFITS explained · keto vs intermittent fasting · optimal ketone level · keto-labeled products · fruit on keto · MyFitnessPal for keto
• Videos: the December 2019 reboot Live · reboot week one · New Year reset · make decisions, not mistakes · back into ketosis after a carb-heavy meal · lazy keto, the original file