Bacteria aren’t always bad! In fact, your digestive tract is loaded with colonies of these little guys. While some can be harmful, most are helpful. Having a good balance of bacteria in your intestines (aka gut bacteria) can be a critical piece of your overall health puzzle.

Less than ideal gut bacteria have been linked to depression, anxiety, overeating, food cravings, brain fog, fatigue, diabetes, obesity, cancer, irritable bowel syndrome and intestinal damage, among other issues.^1-5 Tending to the needs of the tiny bacterial warriors in your gut can be hugely beneficial to your wellness. Here’s are four groups of foods you can eat to support your gut health:

Probiotic foods

What they do: Probiotic foods contain the good bacteria that can help reinforce the armies in your gut. Different strains of probiotics have been researched for different health benefits. For example, L. plantarum and L. rhamnosus are linked to lower levels of stress hormones and increased amounts of intestinal building blocks.^{1, 2} L. heleveticus and B. longum improved stress responses in mice.⁴

How much: Since research into the benefits different strains of probiotics is still in the works, there is no official probiotic recommendation.

How to get them: Foods that are fermented often retain healthful bacteria all the way into your digestive system. Fermented foods like yogurt, kombucha, miso, sauerkraut, and kimchi all contain healthful probiotics.

Vitamins A and D

What they do: Both of these vitamins are linked to improved intestinal and mental health.¹

How much: For vitamin A, men should aim for 900 mcg and women 700 mcg per day. For vitamin D, aim for 600 IUs per day unless you’re over 70, then boost that to 800 IU daily.*

How to get them: Boost vitamin A intake with a serving of sweet potato (1403 mcg), spinach (573 mcg), carrots (459 mcg), cantaloupe (135 mcg), red peppers (117 mcg), or mango (112 mcg).

We get vitamin D primarily from exposure to sunlight, but if your area lacks that for some or all of the year (heyyyyy Western Washington!), try a serving of salmon (447 IU), canned tuna (154 IU), and dairy or dairy alternatives with added vitamin D (115-125 IU). For many living far from the equator, a vitamin D supplement can be a wise idea, but ask your doctor to check your vitamin D status first.

Omega-3 Fatty Acids

What they do: Supplementation with the omega-3 fatty acids EPA and DHA is linked with improved gut bacteria and reduced anxiety- and depression-related behaviors.⁴

How much: 1.6 g per day for men, 1.1 g per day for women.*

How to get them: Different forms of omega-3s are absorbed and utilized at different rates. To get the most usable EPA and DHA, eat a serving of salmon (1.5-1.8 g), mackerel (1.0 g), or trout (.84 g). For non-fish-eaters, plant-based sources of omega-3s contain ALA which can be converted to EPA and DHA, but only about 15% of the ALA is converted. These ALA sources include a serving of chia seeds (5.06 g), flax seeds (2.35 g), black walnuts (.76 g), and edamame (.28 g). If you aren’t likely to meet recommendations with food, a daily omega-3 supplement can back you up. Be sure to choose one that is “burpless” or “enteric coated” to avoid fishy-smelling breath.

Prebiotic Fibers

What they do: “Prebiotic fibers” are specific types of fiber that the bacteria in your gut like to snack on. Keeping a healthy colony of good bacteria well-fed can keep your intestinal lining strong and regulate digestion.^{1, 4-5} For those who already have a bacterial imbalance or a condition like inflammatory bowel disease, some of these can actually worsen symptoms. Talk with your doctor if you have any concerns about your gut health.

How much: There isn’t a specific recommendation for prebiotic fiber intake, but 25-30 grams of fiber covers it for most adults.*

How to get them: Most whole plants foods are good places to find fiber. For prebiotic fibers, go for lentils, kidney beans, apples, currants, dates, figs, and whole grains like wheat, rye, and barley.

*Recommended intakes and food nutrient contents were obtained from National Institutes of Health fact sheets. Children and pregnant or lactating women may have different recommendations.

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1. Bischoff SC, Barbara G, Buurman W, et al. Intestinal permeability – a new target for disease prevention and therapy. BMC Gastroenterol. 2014;14:189. Accessed from:  https://bmcgastroenterol.biomedcentral.com/articles/10.1186/s12876-014-0189-7.
2. Carabotti M, Scirocco A, Maselli MA, et al. The gut-brain axis: interactions between enteric microbiotia, central and enteric nervous systems. Ann Gastroenterol. 2015;28(2):203-209.
3. Galley JD, Nelson MC, Yu Z, et al. Exposure to a single stressor disrupts the community structure of the colonic mucosa-associated microbiota. BMC Microbiol. 2014;14. Accessed from: https://www.ncbi.nlm.nih.gov/pubmed/25028050/
4. Foster JA, Rinaman L, Cryan JF. Stress & the gut-brain axis: Regulation by the microbiome. Neurobiol Stress. 2017;7:124-136.
5. Oriach CS, Robertson RC, Stanton C, et al. Food for thought: The role of nutrition in microbiotia-gut-brain axis. Clin Nutr Exp. 2016;6:25-38.

And just like that, 3 weeks of intermittent fasting is over. In the last week, I changed the structure of my intermittent fasting a little bit. I followed a pre-made intermittent fasting plan that had a 12 pm – 8 pm eating window and planned meals and workouts. The workouts were more targeted for fat loss and not for muscle building (which were my goals with my previous workouts). Changing the workouts allowed me to aim for slightly lower calorie goals since losing fat requires fewer calories than gaining muscle.

Let’s review the entire three weeks, shall we?

How it Went:

Unfortunately, I did not enjoy the experience of intermittent fasting. I’m a lifelong breakfast eater – can’t even remember ever skipping one – so not eating until 10 am or noon (depending on my window) was pretty miserable. I was super hungry, weak, and tired in the mornings, and I noticed that I was more tired as the three weeks went on. I’m not sure if this was related to the eating schedule itself or not, because I also realized that throughout the three weeks I ate fewer vegetables than normal. This was sort of an interesting “side effect” of the eating schedule. Because I was trying to fit all my macros in a small window (and was full throughout most of that window), I ate vegetables less often because I didn’t have space for them! For the most part, vegetables have very few macronutrients (carbs, protein, or fat) and a lot of micronutrients (vitamins and minerals). I often recommend clients increase vegetable intake to help with fullness without adding a lot of calories or macronutrients – the opposite happened here! I was so full throughout the eating window that I strayed away from veggies and towards things that were going to help me meet my macro goals. As a result, my vitamin and mineral intake was much lower than normal, and could definitely have caused my tiredness.

One positive change I noticed is that I liked not eating later in the evening. There are reasons to avoid eating close to bedtime, and having a set time that my eating window “closed” prevented me from going to bed on a stomach full of energy I didn’t need, as well as habitual (not hunger-driven) nighttime snacking and desserts. I usually felt pretty good in the evenings.

As a side note, I love to cook and eat food in general, but I tended not to look forward as much to eating because I was either hungry and waiting to eat or full and had to eat anyway. Eating this way was much less enjoyable and satisfying for me than intuitive eating on a schedule that works well for my body.

What I Learned:

While reviewing the research on intermittent fasting this week, I discovered that researchers have almost exclusively studied alternate day or 5:2 fasting protocols rather than the 16:8 protocol that I followed. If you’re confused about what those protocols mean, check out this post. I wish I would have read through more research before I started, because I might have followed those protocols instead just to match the research.

From a dietitian’s perspective, I learned that there are certain people with certain goals who are good candidates for intermittent fasting and for whom it might work wonderfully. In fact, throughout my time on this diet I met several people (or found out about people I already knew) who use intermittent fasting to regulate their intakes and benefit their health. I plan to summarize characteristics of those folks in an upcoming post! The research is clear that intermittent fasting is one way to achieve quite a few health goals (though there are other ways!). In my practice, I will keep intermittent fasting as another option in my dietitian “tool belt” to help create plans that best match each client’s personality, lifestyle, and goals.

How I did and What Changed:

Overall in 3 weeks, I lost 3.6 lbs, 1.75″ from my waist, 1″ from my thighs and 1.6% body fat. Not too shabby!

The third week is on its own because when I changed my workouts, my calorie and macro needs changed. The meal plan I used that week must have been built on different macro targets than I had set, because I ended up higher on fat and lower on carbs and protein in general. I did the best at hitting my macro goals in the second half of week two, when I broke my needs down into a schedule with macro goals at each meal. It’s important to note here, though, that in the research studies, they often did not track macros or make sure that subjects were meeting their calculated macro needs. In fact, in many of the human studies, the subjects often did not end up meeting their calculated calorie needs.

How it Went:

I’ve still been so hungry in the mornings waiting to break my fast. This leads to crabbyness (the severity of which depends on who you ask…). Then, once I’m able to eat, I feel like I’m constantly eating to hit my macro goals. Eating when I’m not hungry leads to crabbyness. These are unfortunate happenings. During this week I missed my macros for a couple days and one morning hit a blood sugar low during my workout that forced me to realize I need more structure to get my macros in throughout the day. You can read about that here. After I created a more specific eating schedule, I was able to get my macros in a little easier, but I still felt hungry in the mornings and very full during my eating window. I haven’t really felt great at all since I started intermittent fasting.

On the flip side, my pants are definitely fitting better and I can tell that I’ve lost a bit from my waist overall. The measurements don’t reflect it this week because, unfortunately, this is the nasty week of water retention (or as my husband and I refer to it, the “natural disaster”). I expect that next week’s numbers will go back down again.

What I learned:

My fitness goal right now is primarily to gain strength and muscle and maintain cardiovascular fitness and flexibility. I’ve been using a heavy weight lifting routine (along with some moderate cardio and yoga) to achieve that goal for several months now. Lifting heavy and gaining muscle requires an increase in calorie intake to sustain muscle building and recovery, but I’ve found that I really can’t comfortably meet that goal in an intermittent fasting window. When I was eating normally, I didn’t have any trouble meeting that goal because I had more time to digest food before eating again.

I lamented about my struggles to my intermittent fasting coach friend Emily Arger, who offered to let me try her 7-Day Whittle Your Waist plan. The workouts included in her plan are designed to pair better with intermittent fasting than my heavy lifting plan, since I won’t need as many calories/macros. The main goal of the plan (as you might gather from the name), is fat loss. This is a shift from what my actual personal goals are, but I learned that heavy lifting/muscle gain is a very tricky thing to accomplish while intermittent fasting, at least for me. I started her new workout plan today, which includes 25-30-minute Tabata-style high intensity interval training (HIIT) workouts. My cat was impressed…and possibly confused.

How I did and what changed:

Today marks the completion of my first week on intermittent fasting! I’m sitting here waiting for my eating window to open, so I figured I might as well hammer out a blog post. If you’re not sure what I’m talking about, go here to read about my intermittent fasting experiment. Here’s a quick rundown on my week:

How it went:

It’s been a little rough, to be honest. I’m starving in the mornings waiting to eat, pretty much no matter what I’ve eaten the night before. My hunger was a little better when I hit my macros perfectly (or darn close) the day before. At the beginning of a day, it feels impossible to be satisfied once I start eating, then I find myself stuffed with only two hours left to go in my eating window. Then I’m feeling like I should eat because my window is about to close and I know I’ll be starving in the morning if I don’t eat. As I am generally a promoter of intuitive eating (creating an eating schedule based around your body’s own natural hunger cues), this is totally backwards to me. I’m not eating when I am hungry, and I’m eating when I’m not hungry. Not to mention the fact that when I’m starving, I’m much less likely to choose healthy options. For me, my desire for Cajun tots and nachos with cheap, plasticky cheese is directly proportional to the length of time I’ve been hungry. Thus, I struggled to stay within my fat goal. Hunger cues are adaptable, so I’m curious to see if these issues improve in the next two weeks.

I haven’t been hungry most evenings, even though I stop eating at 6 pm and don’t go to bed until around 10 pm. That’s not too much of a surprise, since I’m typically hungry every 4 hours or so normally.

One pleasant surprise: working out while fasted has not been that tough. I like to work out in the mornings and did not want to change that schedule even though I was fasting, but I was worried. I get low blood sugar, especially when exercising, so I was really concerned about completing my normal workouts while fasted. Turns out, working out actually distracted me a bit from my hunger. I did schedule my workouts to end right at 10 am as my eating window opened, because I’m always extra hungry right after my workout. That part has been going great!

What I’ve learned:

Intermittent fasting is probably a great option for a certain type of person – an intermittent fasting “candidate,” if you will. This person is probably not used to eating breakfast or can easily skip breakfast without too much notice, likes to eat larger meals, doesn’t have issues with high or low blood sugar, and has irregular or non-existent hunger cues.

On top of that, a good fasting candidate has a schedule that can work with their fasting instead of against it. Because I work from home, I am mostly able to eat when my window opens, but I have thought about the fact that if I were working my former full-time job, it would be very difficult to follow intermittent fasting. I can’t imagine waiting any longer to eat than 10 am, and 10 am would not be a realistic time to eat at my desk job.

It’s also possible that this person has a sedentary lifestyle so they do not need to eat often to meet their energy needs. I often teach about matching energy needs with energy intake throughout the day, which is tough to do if you’re active for 12 hours but only able to eat for 8.

If these characteristics describe you, you may be a great candidate for intermittent fasting.

How I did and what changed:

Even though my weight stayed the same, I did lose an inch from my waist and another from my thighs during this week. One of the claims of intermittent fasting is that it will promote fat loss, particularly in the abdominal area. My scant week on the diet shows that could be the case! Keep checking in for more updates on what the research says about intermittent fasting.

Be sure to enter your vote for Dietitian on a Diet’s next feature! The runners-up are:

High Intensity Interval Training (HIIT)

This is a style of exercise training that involves training at…well, high-intensity intervals. This pattern of exercise involves alternating between lower- and higher-intensity bouts of exercise. Research shows that incorporating high intensity intervals can provide many of the same benefits as lower-intensity exercise, but with a shorter amount of time spent exercising. HIIT workouts are often promoted for fat loss, aerobic fitness, blood sugar management, decreasing inflammation, and improving cholesterol.

Intermittent Fasting

The term “intermittent fasting” has been used to describe a wide variety of eating styles and schedules, all based on the premise that fasting has metabolic benefits. These eating styles incorporate regularly scheduled “fasts”; some include complete fasts for 1 or more days per week or 1 week per month, but often (and for the style I would be following) intermittent fasting involves limiting the “eating window” to a certain part of the day and fasting for the remainder. The primary goals with intermittent fasting are often to 1) lose weight, 2) increase energy, or 3) reduce inflammation.

Budget-driven Meal Planning

This is actually a brain-child of mine, compiled from everything I have learned about how to drive the cost of healthful groceries down as far as possible. This way of purchasing food and eating has cut many of my clients’ grocery costs by 25%, even while eating healthful food. One particular client, with a family of 8, decreased her grocery bill by 50%! In this I will share what we spend on groceries, where we shop, how I save money, and how I do it all while eating healthfully.

Be sure to vote for the diet or exercise plan you most want to learn more about!