How Long Does it Take to Feel Great on a Plant-Based Diet? (Beating Failure to Thrive)

Posted by:Lindsay S. Nixon Category: Advice

Most commonly, we hear stories of individuals who went plant-based and felt great. They had more energy, mental fog lifted, less stress, started sleeping better, their brain got sharper, their tummy troubles vanished, they had a new hunger for life, their sex drive improved (as we learned with our plant-based guys mini series) and so on. There are so many benefits people feel after switching to a plant-based diet that it would take too many blog posts to name them all.

My Dad, who went plant-based after having a heart attack, wrote this blog post, "What it really means to feel better" 8 months after making the switch and I think his sentiments capture the point I'm making.  

I also love what MaryLou said in her Herbie of the Week story, "you really don't know how sick you are until you know how it feels to be well."

That sentiment is something we hear pretty regularly with our Herbies of the Week. In fact, it's even something *I* said in my post, 10 Reasons why I'm Plant-Based (Vegan).

I wrote, "I never realized how sad and weighed down I felt until I wasn't sad or feeling weighed down anymore."

Yet some people don'tfeel amazing immediately or right after the switch. They.... fail to thrive. 

Every couple of weeks I'll get an email or see a comment on Facebook asking questions like:

"How long does it take to feel great on a plant-based diet?" 


"I totally believe that eating plant-based is the best thing I can do, but I don't feel great. I can't keep going on feeling like crap. Why don't I feel all these amazing benefits I hear about?" 

Anyone who makes a change in their diet (even a positive change) will experience the symptoms of that change. 

For some, they feel great immediately and spend the rest of their life on Cloud 9. (We can all wish to be that lucky!)Most people, however, have a few rough days, typically at the beginning. 

Some individuals experience detox symptoms — aches, headaches, fatigue, irritability — your typical flu-like experience. Others may have no physical pains, but they have mental and emotional challenges. 

Some people feel crappy for weeks as their body fights through withdrawal caused after years of food addictions. 

I can't count the number of times clients came back to me after completing the Supreme Slimdown or the Bikini Blueprint (or just changing to a 100% plant-based diet on their own) and said, in hindsight, "Wow I had no idea how addictive fat, sugar and salt really was — and how badly I was addicted!"

If you've ever quit caffeine — coffee or soda, you know what I'm talking about. You don't think you're hooked until you try to go without it and BAM! A headache hits you like a train two days in. 

I've even known a few people who seemed to have no symptoms whatsoever and then the bill came, with a late notice, several months later — time to pay up. 

I'm not a doctor and even if I was, I think it would still be too hard for me to come up with a one-size-fits-all answer or explanation why some people feel great right away and others fail to thrive. 

I think the experience is just going to be different for everyone, mostly because we all come to a plant-based lifestyle from a different place. What might be a small change for one person could be a huge change for someone else. 

It's where we came from that often dictates how our experience will be. How far we go with our dietary change can also affect what our experience is like. 

For example, I had a client who came to me because she wasn't feeling as great as she expected. "I went vegan because I kept hearing how great you'll feel" she explained, "but I don't feel great. Better I guess, but not GREAT!" 

It didn't take long for me to figure out why. She'd been eating vegan, true, but vegan junk foods were still in her diet. I told her it's like a lottery ticket, you have to get all the numbers right to get the big jackpot. If you're only going half way — if you've only got a few winning numbers on your ticket — you're going to get a smaller prize. 

Once we removed the junk food, the oils, the excess salt and sugar, the processed garbage, and got her on a more whole foods diet, she found that greatness she sought after.

Another friend of mine was a total candy addict. She actually carried candy in her purse so a sweet fix wasn't more than a hand reach away. Eventually, my pal came to accept her relationship with candy wasn't a healthy one and she also wanted to lose weight. 

I went to her house and helped her throw out all her candy. For the first day, she was okay. By the second, she complained of "feeling like garbage" and by that night, she felt so awful that she went to the gas station, bought and ate jelly beans. "I felt so much better!" she said, "maybe I have hypoglycemia or something." I can't dance around my thoughts with flowery words when woken out of bed at 11 p.m., so I snapped, "or maybe you just have a serious sugar addiction." 

That hit her hard. The next morning she called and agreed, she had a problem. She was willing to do whatever it took. I won't lie. It wasn't easy.She went through horrible withdrawal from her sugar addiction. She felt terrible for days. It was painful to see her in pain, but she got through it and never went back. 

That was an extreme case, true, but many of us have or had some kind of addiction to food, just on a smaller scale. It may not even be a physical one, it can be a mental one. It can be emotional. 

I've veered a little off course, but my point is, when you make a change, you have to respect that change and that change is going to happen.Your body (and mind) has to adjust. 

I sometimes compare it to getting a new puppy. The puppy is so cute and just loves you to death. There is a clear, wonderful upside right off the bat to having this new puppy in your life. Yet, the puppy, cute as he is, requires you to develop some new routines. Some are easier to get used to than others.  Remembering to put food down is great. You welcome that new routine. Having to take the puppy out to do his business every few hours, including in the middle of the night because he woke you up, not as awesome. The puppy can really test your patience! But ultimately, you find your strive with the puppy and equally as important: the puppy doesn't stay a puppy forever. The puppy grows up and you grow into your life with a dog. And after enough time has passed, you look back and only have fond memories of your dog when he was a puppy. You don't focus on all the pees on the floor or the shoes he ate. 

This is how change is. You have to get familiar with your new life. Your body has to get familiar with your new diet. The body and mind can fight back to change and test your patience, but keep moving forward.Fight back. 


When people come to me, complaining of a failure to thrive, I find in most instances time is the answer. They have to ride it out and break the food addictions and vicious cycles they got themselves into with a poor diet. 

The other common cause is that they're not getting enough calories, particularly carbohydrates, in their new diet. I find people who have been on a lot of "diets" previously, especially restrictive diets, can fall into this trap. Because plant foods, like vegetables, are so low in calories, you have to eat a lot more volume day to day. 

Recently, a man came to me because he was failing to thrive. I looked over his food journal and it was clear why: he was only eating salads. Now, his salads were huge and he was stuffed, but despite how big they were, he was extremely calorically deficient. Big bowls of vegetables are awesome and healthy, but barely 500 calories. No wonder he was so tired and feeling like poo — his poor body was desperate for more fuel. 

We started adding some cooked potatoes and cooked grains to his diet and he instantly felt better. 

Many people who come to me feeling tired or failing to thrive  feel tremendously better once we add some cooked starch into their diet — grains, corn, potatoes, etc.

If you're not feeling your best,take a closer look at what you're actually eating. Are you getting enough calories? Are you eating starches like brown rice and potatoes? If not, try adding those in. 

Also examine if anything still in your diet could be causing you to fail — think of the lottery ticket. 

Next, think about how long you have been eating this way and could you be going through a detox? Withdrawal from a food addiction? Could it be emotional or mental? 

Lastly, if you're still not feeling your best after all these considerations, go to your doctor for lab work. Some people who "fail to thrive" have nutritional deficiencies which are not necessarily "caused" by their new plant-based diet. Many people who eat the standard American diet have nutritional deficiencies. Becoming deficient can happen to anyone, regardless of their diet. The good news is that most are pretty easy to correct and once you're back to where you need to be, you can adjust your diet and lifestyle as necessary.

Above all though, I want to emphasize this: 

The journey is different for everyone. I asked the Herbies on Facebook how soon after the switch did they feel great (and if they had any detox symptoms) etc. and dozens of answers poured in. You can read the entire thread here, but here are a few highlights: 


"Hubby came off 23 yrs of blood pressure meds in 6 wks, high cholesterol (7+) also down to 3.8 in same period. all IBS sxs gone in 2wks. I lost 4 stone over 2 pregnancies in two years.. can't rate it enough.. 2 plant strong kiddies too!" — Jen R.

"About 10 days of cheese cravings...and then poof! No more cravings. Very mucousy in my nose and mouth for about 2 months (gross, I know)...told that was normal detox. No more headaches or tummy issues within days. Also weird, no more morning breath after dropping dairy!! — Jess R.

"It was pretty immediate for me, but I think that had a lot to do with my attitude, too. I was so excited about my dietary changes that my body adjusted in harmony with my positive outlook." — Heidi L.

"Even just switching from vegetarian to plant-based, I noticed some detox symptoms. I developed some acne (could be unrelated), but my skin is looking increasingly better now and I do attribute that to this diet. Going from vegan to plant-based was the biggest change. After cutting out dairy, I noticed that vegan wasn't enough because I had a huge sugar addiction.Cutting out added oils and sugars (AKA not reaching for the vegan pastries) made such a huge difference for me!" — Alicia R.

"My switch was pretty gradual, but I noticed a 'reverse' detox. I was eating 100% vegan at home and vegetarian out and about. The longer I went without eating dairy regularly, the worse I would feel after eating it 'once in a blue moon' at a restaurant. It was as if my body was saying, 'DUDE. STOP FEEDING ME THIS GARBAGE. WHERE'S THAT GOOD STUFF YOU GAVE ME EARLIER?! MORE SPINACH!'" — Maggie O.

"The first few days were bad. The food tasted pretty bland, but only because the food I was eating prior to going plant-based was super salty and super sugary. After that initial week everything has been fine. Food is more flavorful and I can eat veggies raw, which is something I never would've done before. The first week was hard and I was always hungry, but staying strong I've been able to drop nearly 20lbs in one month. I'm very overweight so the weight comes off quickly but my wife and I have felt a great deal better since starting a plant based diet." — James V.

"I detoxed for about two weeks.It was pretty awful — especially the headaches. But afterward, I felt better than I had...well...ever!" — Sarah G.

"Bad detox, night sweats, headaches and nausea. Lasted for 3 days. Now, I just feel awesome." — Steve G.

Related Readings:

Food Cravings and Food Addictions

"The Failure to Thrive: Speculations on the Nutritional Adequacy of 100% Plant-Based Diets", by John Allen Mollenhauer and Michael Klaper, M.D.


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