What are the possible causes for not losing weight despite dieting?

Why Weight Loss Stalls Despite Dieting

The primary reason for not losing weight despite dieting is that you are not creating a true caloric deficit of 500-750 kcal/day below your maintenance needs—most people significantly underestimate their caloric intake and overestimate their physical activity. 1, 2

The Core Problem: Energy Balance Reality

Your body weight is fundamentally regulated by your central nervous system, which actively resists weight loss through powerful biological mechanisms influenced by genetics. 3, 2 This means that simply "eating healthy" or "dieting" without documenting an actual caloric deficit will not produce weight loss. 2

The critical issue: You must create a documented deficit of 500-1,000 kcal/day from your true maintenance needs to lose approximately 0.45-0.9 kg per week. 1, 2 For most women, this translates to consuming 1,200-1,500 kcal/day, and for most men, 1,500-1,800 kcal/day. 3

Why Your Current Approach Is Failing

Insufficient Caloric Deficit

• You likely believe you're eating less than you actually are—underestimation of caloric intake is extremely common and represents the single most frequent cause of weight loss failure. 1
• Without keeping detailed food logs using measuring tools and reading food labels, you cannot accurately assess your true intake. 3
• The quality of food matters less than total calories consumed for weight loss. 3, 2

Lack of Structured Support

• Standard dieting advice without intensive support produces poor long-term outcomes, with the majority of people regaining lost weight. 3, 2
• You need high-frequency counseling (at least 14-16 sessions in 6 months) focused on behavioral strategies, not just dietary advice. 3
• Without weekly contact initially, then biweekly, then monthly support, long-term success is rare. 2

Metabolic Adaptation

• As you lose weight, your body reduces energy expenditure and increases hunger hormones—this adaptation persists for extended periods and makes further weight loss progressively harder. 1, 4
• Your basal metabolic rate decreases with weight loss, reducing the difference between energy intake and expenditure over time. 5

What You Must Do Differently

Create a Verified Caloric Deficit

• Keep detailed daily food logs with measured portions—this is non-negotiable. Patients who regularly record food intake lose significantly more weight than those who don't. 3, 6
• Calculate your true maintenance calories and subtract 500-750 kcal/day. 3, 1
• Weigh yourself at least weekly to verify you're losing approximately 0.45 kg per week. 2, 6

Implement Intensive Behavioral Support

• Engage in a structured program with weekly counseling sessions initially. 3
• Self-monitor your eating habits, physical activity, and weight daily. 1, 6
• Address specific barriers as a mother with young children, including time constraints, stress, and irregular eating patterns. 1

Optimize Physical Activity

• Exercise alone produces minimal weight loss (only 2-3 kg), but is crucial for maintaining weight loss once achieved. 3, 2
• Gradually increase to 200-300 minutes per week of moderate-intensity activity for weight maintenance. 3, 1
• Include resistance training 2-3 times weekly to preserve lean muscle mass during weight loss. 1

When to Escalate Treatment

If you implement these strategies and achieve minimal weight loss within 3 months, you need to intensify therapy. 2

Consider Pharmacotherapy

• FDA-approved weight loss medications should be added to lifestyle modification for BMI ≥30 or BMI ≥27 with weight-related comorbidities. 3, 2
• The most effective current option is tirzepatide, producing 21% weight loss at 72 weeks. 3
• GLP-1 agonists (semaglutide, liraglutide) produce 8-15% weight loss. 3

Consider Bariatric Surgery

• For BMI ≥40 or BMI ≥35 with comorbidities when less invasive methods fail, bariatric surgery produces 25-30% weight loss at 12 months. 3, 2

Critical Pitfalls to Avoid

• Do not rely on dietary supplements marketed for weight loss—they lack clear evidence of effectiveness. 3, 1
• Do not assume that eating "healthy foods" alone will produce weight loss without creating a caloric deficit. 2
• Do not expect exercise alone to produce significant weight loss. 3, 2
• Do not attempt weight loss without structured support and frequent contact—this approach has a very high failure rate. 3, 2

Medical Factors to Screen For

Have your physician evaluate for:

• Medications causing weight gain (antidepressants like mirtazapine or amitriptyline, antihyperglycemics like glyburide or insulin) and consider alternatives. 3
• Thyroid dysfunction, metabolic syndrome, or insulin resistance that may impair weight loss. 3, 1
• Sleep apnea, which is common with obesity and affects weight management. 3

The Bottom Line

Weight loss resistance is primarily behavioral and environmental, not metabolic. 2, 7 You must create and document a true 500-750 kcal/day deficit through measured food intake, engage in intensive behavioral support with frequent contact, and monitor your weight weekly to verify progress. 1, 2 Without these specific interventions, long-term weight loss is extremely unlikely regardless of how "healthy" you believe you're eating. 3, 2