I tried Silicon Valley's favorite diet using a meal-replacing keto shake - here's the verdict

The shake consists of Sated-branded powder mixed with water, plus a fatty oil blend. It includes olive, flax, and coconut oils and packs a whopping 280 calories per scoop, providing the heft of my 400 calorie breakfast shake.

People on the keto diet usually get at least 60% of their calories from fat — nearly double the recommended daily dose.

When prepared as a 12 ounce shake, Ketolent packs 35 grams of fat into my breakfast, providing nearly half of my recommended total fat for the day (45%), and 60% of my daily saturated fat.

It's not even 10 a.m. They weren't kidding about this eat more fat business.

The keto diet is focused on healthy fats. But when I'm not slurping shakes, it can be a confusing eating plan, because some healthy foods like carrots and beans are banned.

I freaked out on day one of my new experiment when I realized that I'd inadvertently added half and half into my coffee.

A couple teaspoons added to mellow out my morning cup amounts to more than one additional gram of carbohydrates a day, which is a lot when trying to stay under the rigid 20-grams-of-carbs-a-day version of the keto plan.

And I have to completely ban carbohydrate-rich foods that are staples of a cheap, healthy diet — like beans, quinoa and whole grains.

It all makes me glad I don't have to worry about what keto-approved food to eat for breakfast, before my brain (and caffeine) kicks in. Instead, I just mix up a Ketolent shake.

The three keto shake ingredients: oil mix, powder, and water, all get poured into a big blender bottle. I fill it up to the 12 ounce mark, and give it a good jostle.

It's not the worst breakfast shake I've ever had. Ketolent tastes like a slightly-less-sweet version of brownie batter, without any weird, whey-like aftertaste. I was impressed.

My biggest complaint about the Ketolent shake was its clumpiness.

When I asked the company about this, they said they're still toying with the consistency. Others on Reddit seemed to agree with my critique.

Sated is not the only startup hoping to court the keto crowd. Other companies, like Ample, offer single-serve powders that come in ready-to-blend plastic bottles.

The meal plans are taking off with people who think they have better things to do than eat: another popular meal replacement shake, Bear Squeeze, broke a food campaign record on crowdfunding site Indiegogo. The company bills itself as creator of "the world's healthiest keto meal shake," and it raised over $65,000 for the new beverage on day one.

My first day on the diet, I couldn't last until lunch on the shake. Snack time! How about a nice juicy apple and a little cheese, right? Wrong.

Like carrots, apples are too sugar- and carb-loaded to be a part of this eating plan. A single red apple, with 25 grams of carbs inside, is a major no-no this week.

Guess it's going to be a lot of black coffee, cheese and fatty nuts (minus the cashews — also too many carbs) to tide me over for the next four days.

Besides breakfast shakes, avocado and chicken lunches, fish, and black coffee will help get me through until dinnertime the rest of this week. At least, I hope so.

Fortunately, salads are still allowed on the keto plan. Normally, I go light on salad dressing, but not tonight.

I know that leafy greens like kale and arugula are welcome on a keto diet, and meats and nuts are OK, but I wasn't sure about tomatoes. I quickly Googled and found out they're alright in moderation.

But it seemed crazy that I had to Google every suspect salad ingredient. That's another point for the Ketolent shake, which I don't have to worry about scrutinizing for hidden carbs or sugars every time I take a sip.

One other potential keto slip-up that I didn't even consider until I started munching on the salad: Canola oil.

Canola oil is too inflammatory and processed to be allowed, keto followers say. But Harvard nutritionists suggest canola oil is a better choice for your heart than saturated fats (which are darlings of the keto diet), because it lowers "bad" LDL cholesterol and heart disease risk when compared to butter and beef fat.

Another day when I had turkey and cucumber pinwheel rolls for lunch I worried that I might have messed up, because they were sandwiched with a processed, bright yellow cheese.

Keto followers often choose high-fat unprocessed cheeses and meats, because processed foods can pack so many additives. A slice of processed cheese has more than two grams of carbs and 1.4 grams of sugar, so it's not an ideal choice for ketoers.

Ketolent's shake, which is built on a base of milk protein isolate (like so many meal replacement shakes) is also a processed food. It includes a sucralose sweetener, the thickener guar gum, plus more than a dozen other ingredients.

Because I have a raging sweet tooth, I often scarfed down a little handful of blackberries for dessert, or chased dinner with some dark chocolate.

While apples are sugary off-limits treats for strict keto-ers, a handful of blackberries has less than five grams of sugar and fewer than 10 grams of carbs.

It's a splurge if I'm aiming to stay under 20 total grams of carbs a day, but it's doable.

I also learned that very dark chocolate (like, 85%) is alright, because it has very little sugar. The good news was I wasn't craving sweets as often as I normally do. I knew they were off-limits for a few days, and that was fine. Plus, my breakfasts of Ketolent were always chocolatey.

The great thing about the plan is that it made me drink a ton of water. I was a tad thirstier than usual, but I also downed copious amounts of H2O because I was worried about the health of my kidneys.

The keto diet is designed to be high-fat, but keto dieters can also take in a lot of protein on the plan.

The Ketolent shake has 18 grams per serving, while other staples of the diet, like meats, fish and cheese also pack a protein punch. Because high-protein diets can put extra stress on kidneys, I made an effort to guzzle more water than usual the week I tried to go keto. It wasn't hard to do; I was craving more water anyway.

Some keto dieters complain of lower back pain, which is another sign that their kidneys might not be doing well. I didn't want to risk it.

If I learned one thing over the course of this week, it was this simple truth: sugar was hiding everywhere in my diet. I had to keep checking every label to make sure I wasn't getting too much (when I wasn't drinking meal shakes).

Even my full-fat plain yogurt had 6 grams. Ugh.

While this was a short-term experiment spanning just four days, I lost a few pounds, and also weaned myself off some sweet routines.

By day three, I was beginning to wonder if the bottom of my belly was looking a little paunchy from all that fat.

But clearly that was my imagination, because the scale said I'd lost about three pounds since this experiment began.

Given that this was a short-term test, it's entirely possible most of that was water weight.

Not all the results were pretty.

My number one complaint: I was consistently paranoid about my breath.

Ketosis prompts the liver to turn fat into three different kinds of ketone body molecules. One of these is called acetone, and it is released in urine and through the lungs. The result is keto breath. People say it can be kind of like a sweet nail polish remover smell, but I was just worried that my breath was bad.

Toothpaste maker Colgate suggests keto dieters chew sugar-free gum and add natural breath fresheners like cinnamon and mint into their tea. Instead, I just tried to keep my distance when I spoke to people.

Sometimes I also felt like I had a sore throat.

People on the diet often complain of a "keto flu" that can kick in in the first week of this diet, when the body is switching from burning carbs to fat. I felt nauseous and dizzy on more than one occasion, and worried I was getting sick because of my sore throat. It usually went away after about an hour or two.

Final complaint: my skin was an oily wreck on this plan.

By day two, my cheeks were breaking out in a way they haven't since high school. Apparently, all this extra fat I was eating was taking my skin on a field trip back to puberty.

By the fourth day, I was ready to call it quits. It was time to find out: did I enter ketosis, or not? There were certainly some compelling signs I was in that starvation-like metabolic state where the body starts relying on fat for fuel.

According to this urine test, I was in a "moderate" state of ketosis.

It's important to note that the test strip I used only tracks the presence of ketone bodies excreted in urine. Many keto-ers argue this is a useless measurement, because it isn't as accurate or immediate a measure of ketosis as a blood ketone monitor.

While it's true that a urine test strip only measures the kinds of ketones that are excreted in the urine, and is not direct evidence of a keto metabolic state, it is nonetheless a rough indicator that in the not-so-distant past, my liver was likely producing ketones.

People who've adapted to the keto diet over weeks at a time may no longer excrete very many ketone bodies in their urine, but after just a few days on the diet, it's a promising sign. Still, it's not a sure bet.

Most people who are strictly following a keto diet can be pretty confident they're in ketosis after three to four days. But the exact amount of time depends on a host of factors, including what you eating and how active you are.

I was glad when the keto experiment was over. While the diet clearly has many fervent followers, some experts worry about possible long-term effects.

The keto diet is a proven treatment for tough-to-control epileptic seizures in children, and people with type-2 diabetes who are trying to lose weight and improve their blood sugar can also benefit from the plan.

But that doesn't mean everyone should go keto. Kinesiologist Edward Weiss worries that people without serious health conditions who are trying the plan might be pumping their bodies full of dangerous acid, and avoiding some of the "healthiest foods we know of," like fresh veggies and legumes.

"What's sort of scary is that [the keto diet] is an experiment that the population is doing on itself," he told Business Insider in May. "No drug company would get away with introducing a drug in the population without thorough research."

People following a keto plan may need to supplement their diet with more vitamins, and no one who's pregnant, has chronic kidney disease, or is prone to gouty arthritis should try it.

Even though keto fans argue that it takes weeks to reap the benefits of this diet, like better focus and less fatigue, a four-day trial was enough for me.

I went home, put a slice of cheese on one formerly-forbidden cracker, and poured myself a glass of carbohydrate-laden wine, with no regrets.

I'd never want to do this project long-term, but it was nice to eliminate all the choices and decisions around food for a bit, even if it made me second-guess nearly everything I put in my mouth.

Except, of course, that Ketolent shake.