No Matter How Little I Eat, I Can't Lose Weight

Written by: Natalie Pirolli, MS, RDN, LDN, RYT | November 7, 2023

I'm not sure if it comes with the territory of being a dietitian or being a female in a very weight- and appearance-focused world, but I can't tell you how many times I hear things like: "I can't eat that, I'll gain weight"

"I gain weight just looking at dessert"

"My husband can eat whatever he wants, but I can't"

"No matter how little I eat, I still can't lose weight!"

Especially that last one. Over the years I've worked with several clients who were eating so little yet not losing or were actually gaining weight. I often see that chronic dieters' weight not only yo-yos but also shows a gradual upward trend over time (especially in those who start dieting at or around "normal" weights). While there are many factors outside of our control that influence our weight (like genetics, age, set point, stress, socioeconomic status, etc.), I find there is a common denominator in these clients: not eating enough.

There is a physiological reason why eating very little does not always result in long-term weight loss: our bodies go into survival mode when we're not receiving enough nutrition. Undereating sends our body the message that access to food is scarce, so it starts conserving energy by slowing down our metabolism, digestion, hormone production--all body processes. It may also start increasing hunger cues, often as cravings for simple carbs/sweets (have you ever walked in the house after a day of not eating enough ready to devour all of the carbiest carbs in sight?) and favoring things like fat storage in an attempt to protect us from the perceived "famine" we're in. Not to mention the toll that this chronic state of stress takes on our mental health, which can also lead to more emotional eating. All of these things can lead to the weight loss "plateau" dieters typically experience after following a diet for some time and the eventual weight gain that can result from chronic undereating or yo-yo dieting. In other words, they're the reasons diets and restrictive eating often fail to give us the long-term results we're looking for.

"But I feel like I have more energy when I (start a new diet, intermittent fast, skip breakfast, eat less...)"

That is your stress response kicking in. Cortisol and epinephrine (adrenaline) levels rise as we enter this panic mode, and initially increase things like our feelings of alertness, concentration, and energy. Cortisol levels naturally rise in the morning, but dieting or undereating can elevate them above the normal levels, making us at first feel increased energy/focus in the morning. Chronic undereating, whether it is intentional (dieting, fasting) or unintentional (going through a busy/stressful time, losing your appetite), contributes to chronic stress. In other words, when we're not meeting our nutritional needs our bodies do not feel safe and set off the fight or flight response. Though this initial energy boost may feel good, it can actually be wreaking havoc on our physical and mental health.

Cortisol is an important hormone and beneficial when we have it within normal amounts. In addition to getting our bodies ready to deal with potential stressors, it can also help to reduce inflammation and regulate blood pressure and blood sugar levels, amongst other things. But too much cortisol or chronically elevated levels can result in:

• Insulin resistance (issues managing blood sugar levels) and diabetes

• Weight gain (typically in the abdominal area)

• Immune system suppression

• Fertility issues

• Thyroid dysfunction

• Gastrointestinal issues

• Cardiovascular disease 

And the irony is, we think we're doing a good thing by cutting calories or eating as little as possible!

In a society where we demonize fatness, value thinness, expect mothers to "bounce back" to pre-pregnancy weights in the blink of an eye and never show signs of aging--the pressure to look a certain way is high, to say the least. But we need to ask ourselves: at what cost?

The problem is, eating enough is rarely mentioned as a good thing. Do you know anyone who proudly shares how satisfied they feel from nourishing themselves well? Or have most of us learned to wear "I haven't eaten anything all day!" as some kind of a badge of honor? In our society, not only is busyness (and being too busy to remember to eat) coveted but there is something we find admirable about a person who eats very little. We think it shows discipline, self-restraint, and (on some twisted level) self-care or self-love.

We also receive the message in so many different ways (weight loss ads, social media influencers' "what I eat in a day for weight loss" videos, the medical community) that in order to be healthier, happier, more confident--you name it, we should be eating less. I'm here to tell you that is simply not true; we should be eating enough to support our body and all of its daily functions in order to be healthy and feel our absolute best.

Not to mention, there are so many life stressors outside of our control. Making our bodies feel safe by nourishing them adequately is one of the simplest, most profound ways we can help reduce stress in our lives. (And practice self-love).

I don't think I know a single person who hasn't dieted or felt influenced by diet culture in some way (myself included!), so don't feel bad if you have felt or currently feel in that calorie-restrictive mindset as a means to improve your health or happiness.

If you aren't sure if you're eating enough, here are a few signs your intake may be too low:

• Low or inconsistent energy levels

• Feeling anxious, stressed, or more easily overwhelmed

• Irritability or other mood changes

• Poor appetite OR increased hunger or food cravings

• Constipation

• Brain fog or difficulty concentrating

• Irregular or missing periods

• Difficulty falling or staying asleep

• Feeling cold frequently

• Hair loss, thinning brittle nails

• Weight issues (loss, gain, inability to lose, etc.)

Some signs of adequate nourishment include:

• Stable, reliable energy

• Ability to handle stress well

• More predictable, steady moods

• Hunger upon waking and throughout the day before meals/snacks

• Regular daily bowel movements

• Ability to focus or concentrate

• Regular, healthy menstrual cycle

• Ability to fall asleep and stay asleep most of the night

• Normal body temperature

• Healthy hair, skin and nails 


• Weight maintenance without having to "manage" it (i.e., diet, count calories, etc.)

I know the thought of eating more isn't always appealing or necessarily stress-reducing, especially with the outside pressures to achieve a certain body type. However, increasing food intake may not necessarily lead to weight gain. Remember how undereating can reduce our metabolism? Eating enough will increase our metabolic rate making it more efficient at burning/utilizing energy. I've worked with clients who gradually worked their way back to eating enough to support their body's needs and they lost weight or stopped gaining weight (because they were either above their set point weight, or their emotional/binge eating behaviors reduced, or their relationship with food/body improved, or typically, because of a combination of things).

That said, I've worked with clients who were below their set point weight, and eating more, as it should in this case, resulted in weight gain that was necessary for their health. For others, who are at or above their set point weight range, eating enough likely would not cause long-term weight gain (more on set point weight coming in a blog soon!). But trust me when I say it will actually be easier to maintain a healthy body weight, reduce stress and anxiety, and improve overall health and well-being if we nourish ourselves adequately.


Regardless of weight, eating enough (and having a good nutritional foundation) is essential for our health and well-being. It doesn't matter how many supplements we take, miles we walk, minutes we meditate--if we are not eating enough, our other health habits are not as effective as they could be or in some cases may be totally pointless.

If you're undereating, it can help to gradually increase your intake by:

• Incorporating nutrients you may be lacking (for example, are you getting enough protein, healthy fats, and/or carbs?) to meet your needs.

• If you're currently skipping breakfast, start incorporating a protein-rich snack or meal within 30-60 minutes of waking.

• If you're going long stretches without eating, try incorporating a snack that contains at least two macronutrients (carb + protein, carb + fat) so that you're eating every 3-5 hours throughout the day.

Added bonus: these tips help balance our blood sugar levels, which also helps prevent stress (cortisol spikes) in the body! (More on stress and nutrition coming soon, too).

Interested in learning how you can improve your nutritional foundation? Reach out with any questions or book a free 15-minute consultation call. And stay tuned for more by subscribing to my monthly newsletter.