Can Eating Less Speed Up Results?
- Valerie Rider
- Mar 15
- 4 min read
Updated: Mar 18
It feels logical, eat fewer calories, see faster results- problem is solved. But the reality of undereating is sneaky and can create a surprisingly negative cascade.
I've learned all about extremes and moderation in my decade of coaching and practicing balanced wellness (and 11 years of sobriety). High restriction isn't sustainable, and it usually backfires.
For years, I chronically underate and sabotaged my health, fitness goals, and overall happiness. It was an exhausting cycle that ended with periods of overeating and disappointment. I'd love to save you or help you avoid that.
Running on Empty
Eating too little can cause sluggishness, foggy-headedness, irritability, and amotivation. Good energy is more than just feeling awake. It's mental clarity, emotional stability, and a fulfilling life.
Having steady, reliable energy changes everything.
When calories are low, strength decreases, endurance suffers, and recovery slows. The body needs fuel for everything—from powerlifting to BJJ or focusing at work. Undereating slows the brain and body and affects productivity, performance, and vitality.
Metabolism Slow Down
When a person consistently eats less for an extended period, their body adapts. It realizes there's a shortage of calories and begins conserving energy. This phenomenon is known as metabolic adaptation. Think of it like budgeting—if you're short on money, you naturally cut back on spending. The downside of this adaptation is that it slows down your metabolism, making shedding fat even more difficult.
Weight loss researcher Dr. Bill Campbell has shown that chronic undereating lowers one's Resting Metabolic Rate (RMR). RMR is the calories burned when lying awake in bed. A lower RMR means it's harder to lose weight.
Hormonal Chaos
Bodies run on hormones—messengers that tell your body what to do. Undereat chronically, these messengers get nutso crazy.
Thyroid hormones (pivotal for managing metabolism) drop significantly. The thyroid acts like a thermostat, controlling energy, metabolism, and body temperature. When it slows down, everything feels off.
Leptin, the "I'm full" hormone, drops dramatically. Ghrelin, the "I'm hungry" hormone, ramps up. Ever wonder why hunger feels uncontrollable after restricting for a while? That's ghrelin shouting, "Feed me, dumbass!"
The Restrict-Overeat Cycle
Dr. Bill Campbell's research shows that these hormonal shifts can lead to significant
problems with appetite control, making it more likely to swing from restriction to overeating—he calls this the pendulum effect, which you might know as yo-yo dieting.
Your body, craving calories, prompts you to eat significantly more than if calories were never restricted.
Restrict, binge, regret, restrict, repeat.
This cycle damages relationships with food and makes consistent progress nearly impossible.
The kicker is that a lowered metabolism can't handle the increased calories as effectively when returning to eating normally after a severe calorie deficit. The body quickly stores extra calories as fat—this is called "fat overshooting."
Thus the cycle repeats: restrict, binge, gain fat, restrict again.
Muscle Loss: The Unseen Damage
Muscle is metabolic gold—it helps burn calories even at rest, supports strength and mobility, and looks good.
When calories are too low, the body looks for alternative energy sources. One convenient source is muscle tissue. Losing muscle makes you weaker and further reduces your metabolic rate. This cycle is frustratingly common and creates a downward spiral of decreasing metabolism and increasing frustration.
The research supports this: preserving muscle mass during weight loss requires adequate calories, especially protein, and regular resistance training.
Mental and Emotional Toll
Aside from physical effects, chronic calorie restriction messes with mental health. I've experienced firsthand how negative this cycle can be—and trust me, living with constant food anxiety isn't sustainable or enjoyable.
In the 1940s, scientist Ancel Keys led one of the most influential studies on human starvation—the Minnesota Starvation Experiment. Thirty-six healthy male conscientious objectors (WWII) went on a semi-starvation diet for six months, eating around 1,500 calories per day.
The results were shocking. The men lost weight rapidly, but their metabolism slowed drastically. They became weak, constantly hungry, obsessed with food, and experienced depression, anxiety, and mood swings. Even after the experiment ended, many struggled to return to regular eating habits, showing long-term effects.
Sound familiar?
What does this mean for dieting today? Crash dieting doesn't work. When we significantly reduce our calorie intake, our metabolism adjusts to lower energy levels. This adjustment can make weight loss more difficult, potentially lead to binge eating, increase anxiety around food, invoke feelings of deprivation, and cause emotional distress.
The Better Way: Balance and Moderation
Here's the good news: choosing a balanced, moderate approach can avoid these negative adaptations.
The trick to sustainable fat loss is moderation and consistency—not extremes.
Here's what works:
Moderate Calorie Deficits: Aim for a mild calorie deficit—just enough to lose fat slowly, around 0.5 to 1 pound per week. For some very heavy, 2 pounds might be sustainable. This pace helps preserve metabolism, muscle, and sanity. It's sustainable and doesn't trigger intense hunger or hormonal havoc.
Diet Breaks and Refeeds: Take planned breaks from dieting every few weeks. These periods of eating at maintenance calories help reset hunger and satiety hormones, maintain your metabolic rate, and protect muscle mass. Think of it like taking weekends off after a busy workweek—your body and brain need rest.
Prioritize Protein and Strength Training: Protein is satiating, preserves muscle, and boosts metabolism. When combined with strength training, protein helps maintain muscle, increases metabolism, and improves body shape.
Easy Action Steps:
Track calories moderately, but don't obsess.
Eat protein with every meal.
Lift weights 2–4 times weekly.
Schedule occasional diet breaks at maintenance every 4–8 weeks.
Pay attention to your body. If you feel hungry or irritable consistently, it's likely time to eat more.
The reason you started this journey probably wasn't about deprivation but finding a more meaningful and enjoyable way to live.
Eating well isn't about starving yourself thin. Your body is smart—it knows when you take good care of it and responds positively. Nourish it, move it, rest it, and appreciate it. Balance, moderation, and consistency always win.
Have you experienced any of these effects from undereating? Let's chat!
