The 10 Biggest Weight Loss Mistakes

If you're on a weight loss journey, chances are you've hit a few bumps along the way. As a registered dietitian nutritionist who specializes in diabetes and weight management, Ginger Cochran has seen countless clients struggle due to the same common pitfalls. In this blog, Ginger shares the top 10 weight loss mistakes she sees in the clinic, along with evidence-based tips to help you avoid them for long-term success.

1. Not eating enough protein

One of the most frequent weight loss mistakes is underestimating the importance of protein. Protein supports muscle maintenance, improves satiety, and stabilizes blood sugar—all essential for healthy weight loss. Studies suggest that consuming around 30 grams of protein per meal supports optimal metabolic function and appetite control.

Weight loss tip: Include protein at every meal—sources like eggs, poultry, fish, tofu, Greek yogurt, and legumes are all excellent choices. Research shows focusing on more plant-based proteins like edamame, beans, lentils, tofu, and tempeh can have additional benefits on weight, gut diversity, and reduction in chronic disease risk.

2. Focusing only on “calories in vs. calories out”

While calorie balance matters, quality trumps quantity. A diet full of nutrient-dense whole foods—vegetables, legumes, lean proteins, and whole grains—leads to better long-term outcomes than a low-calorie diet full of ultra-processed foods, like those found in many marketed diet meal plans.

Highly processed diets are linked to increased hunger, weight gain, and metabolic dysfunction, even when calorie-controlled, one report highlights.

Weight loss tip: Focus on fiber-rich, whole foods that nourish your body—not just cutting calories. Thankfully, here on the Central Coast we live in a Mediterranean environment. You can find incredible produce, local proteins, and other whole food products at our farmers markets and farm stands. Check out the full calendar of farmers markets happening in the area.

3. Cutting out all carbohydrates

Completely eliminating carbs is one of the most common and misguided weight loss mistakes. Healthy carbs like beans, fruits, vegetables, and whole grains provide fiber, energy, and essential nutrients. They also feed beneficial gut bacteria, which support metabolism and mental health as one report highlights.

Weight loss tip: Choose low-glycemic, high-fiber carbs and watch portion sizes rather than eliminating them entirely. For processed carbohydrate foods like crackers, tortillas, breads, and chips, I recommend making sure they have at least 3g fiber and 15g of carbohydrates per serving. Ideally, choosing whole food carbohydrate sources like berries, beans, lentils, winter squash, and peas—and reducing ultra-processed foods—will give better results.

4. Not drinking enough water

Hydration plays a significant role in metabolism and appetite regulation. Mild dehydration is often mistaken for hunger, which can lead to overeating. Aim for at least 9 cups/day for women and 13 cups/day for men as National Academies suggests.

Weight loss tip: Carry a reusable water bottle and drink consistently throughout the day, especially before meals. For patients who easily forget water, I’ll recommend drinking a glass of water with every meal and snack or using a cup with a straw.

5. Skipping exercise

For long-term weight loss success and maintenance exercise is key. Exercise helps preserve lean muscle mass, which boosts your metabolism. Without it, 25% or more of weight loss may be from muscle tissue according to a study. The quicker you lose, the more muscle you lose. Exercising alongside dietary changes promotes healthy weight loss and maintenance of loss.

Weight loss tip: U.S. Department of Health and Human Services found individuals should aim for 150–300 minutes of moderate activity per week, including strength training to support fat loss and muscle retention. 150 minutes per week is the basic recommendation from the American College of Sports Medicine (ACSM) to start getting the benefits of exercise. If you want to lose weight and maintain it, aim for 300 minutes of purposeful exercise per week according to ACSM.

6. Poor sleep habits

Analysis from The Journal of Clinical Endocrinology & Metabolism confirms sleep deprivation increases levels of ghrelin (the hunger hormone) and reduces leptin (the satiety hormone), leading to increased cravings and calorie intake. It also slows metabolism and reduces motivation to exercise.

Weight loss tip: Prioritize 7-9 hours of quality sleep nightly. Create a consistent bedtime routine and limit screen time before bed. Keep screens out of the bedroom to reduce distractions and improve sleep. Use blackout curtains to reduce light exposure and work to minimize ambient light. For melatonin to be released and help with sleep, we need a dark room.

7. Ignoring stress and environment

Stress affects hormone regulation and eating behavior. Chronic stress can increase cortisol, which may lead to fat storage—especially around the abdomen according to The Journal of Clinical Endocrinology & Metabolism. A chaotic environment can also trigger mindless eating.

Weight loss tip: Practice mindfulness, breathwork, take breaks at work, take time off from work, or yoga, and create a home environment that supports healthy eating. If you are prone to stress eating, avoid snacks within easy reach or view in your desk or kitchen. Place mindless snacking foods in areas that create more effort—like the garage, across the room, or on a high shelf—to give yourself time to check in and create mindfulness around eating behavior.

8. Overdoing it with fruit

Fruit is nutritious, adds fiber to your diet, and is nature’s candy. Many times, I find patients have great intentions by snacking on fruit all day. Unfortunately, the natural sugars in fruit can add up. Overconsumption may spike blood sugar levels and stall weight loss in some individuals. While fruit should not be avoided, portion control is key.

Weight loss tip: Stick to 1 cup at a time and aim to have more vegetables than fruit in your diet. Pair fruit with protein—like string cheese, nuts, seeds, or edamame—to blunt blood sugar spikes.

9. Treating weight loss like a quick fix

One of the biggest weight loss mistakes is viewing it as a short-term sprint instead of a long-term lifestyle shift. Fad diets may lead to quick drops on the scale, but they are rarely sustainable. When we make 20 changes at once instead of consciously adjusting our lifestyle and habits, it’s easier to revert back to old, ingrained behaviors.

Weight loss tip: Focus on habit-building and consistency. Make behaviors goals that include and action and timeline for example, “I will shop and prep vegetables on Sunday.”

10. Overeating “healthy” foods like nuts

Nuts are rich in healthy fats and nutrients, but they're calorie-dense. Research supports that one serving per day—a small handful (about ¼ cup)—promotes longevity, reduces dementia risk, and supports heart health. Many people overdo it with nut snacking and unintentionally add hundreds of calories to their day. One cup of nuts ranges from 600-800 calories, which, when added on top of someone’s usual intake through mindless eating, can lead to weight gain.

Weight loss tip: Pre-portion nuts instead of eating straight from the bag. Be mindful of nut butters too—each tablespoon is about 100 calories.

Final thoughts

Weight loss is a journey, not a destination. By avoiding these common mistakes and making evidence-based choices, you’ll be better equipped to reach your goals and maintain them long-term. Focus on nourishment, consistency, and self-compassion—Need help? Ask your doctor for a referral to registered dietitian nutritionist.