The Problem With Trending Diets

Every diet that goes viral works the same way and fails the same way. It works because it cuts a large category of food and that creates a deficit by accident. It fails because removing food categories permanently is not how human eating works — and the data on long-term adherence is brutal.

A 2014 meta-analysis by Johnston et al. in JAMA compared 11 popular named diets (Atkins, Zone, Weight Watchers, South Beach, Ornish, etc.) over 12 months. All diets produced similar weight loss at 6 months (about 6 kg). By 12 months the differences shrank further. By 24 months — in most follow-up data — there was no significant difference between any of them, and a majority of participants had regained most of what they lost.

Figure reference: Johnston BC et al. “Comparison of weight loss among named diet programs in overweight and obese adults: a meta-analysis.” JAMA. 2014;312(9):923–933. PMID: 25182101. See Figure 2: weight loss at 6 and 12 months by diet brand.

The conclusion the paper made — and that has been replicated since — is that adherence beats brand. The diet you can do for the rest of your life beats the diet that produces 8 kg in 12 weeks and then ends.

What goes wrong, named by name

Keto. Cuts carbs to under 50 g/day. Creates rapid water-weight loss in week 1 that gets sold as fat loss. The deficit is real — ketosis suppresses appetite — but most clients can’t maintain it past 6 months. When they reintroduce carbs, glycogen and water rebound and the scale moves up 2–4 kg in a week, which is interpreted as “the diet failed” rather than what it actually is (water re-fill). The deeper problem: very-low-carb diets are not optimal for muscle building or for high-intensity training, which means the lean mass you wanted to keep is hard to keep.

Anti-inflammatory. Cuts grains, dairy, nightshades, processed oils. Some of these cuts are evidence-based (industrial seed oils, ultra-processed foods); others are not (nightshades aren’t inflammatory for the vast majority of people). The diet works for a while because it eliminates ultra-processed food. It fails because few people can navigate restaurants, family meals, and travel under this many restrictions.

Carnivore. All animal products, no plants. Produces dramatic short-term weight loss because total volume drops. Concerns: fibre intake near zero, downstream effects on the gut microbiome, and a lipid panel that often worsens substantially even when weight drops. Long-term data on carnivore is essentially absent.

Whole30. Cuts grains, dairy, legumes, sugar, alcohol for 30 days. Useful as an elimination tool to identify food sensitivities. Not a long-term diet — and the program itself says so. Most users misuse it as a cycle: 30 days strict, then bounce back, then another round of strict.

Intermittent fasting (16:8, OMAD, ADF). A 2022 randomized trial in N Engl J Med by Liu et al. compared 16:8 IF to standard caloric restriction over 12 months. Both groups lost similar weight. The IF group had no measurable advantage. The take-home: fasting windows aren’t magic — they’re a tool to make caloric restriction easier for some people.

Figure reference: Liu D et al. “Calorie Restriction with or without Time-Restricted Eating in Weight Loss.” N Engl J Med. 2022;386(16):1495–1504. PMID: 35443107. See Figure 2: weight loss curves between TRE and standard caloric restriction groups.

What the trends have in common

Every trending diet provides three things: a story, an enemy, and a deadline. The story makes restriction feel meaningful. The enemy (carbs, fat, gluten, lectins, seed oils) gives the user something to fight. The deadline (30 days, 12 weeks, your “transformation”) gives a finish line.

When the deadline arrives, the user lacks a maintenance plan. Almost no diet on the trending list includes a maintenance phase. So they revert, regain, and start another diet.

What works instead

Habit-stacked, macros-tracked, food-flexible eating. No banned foods, just measurable targets — protein per day, calories within a range, ~25 g of fibre, water, vegetables every meal. This is what the BTZ Weight Well program runs. It’s slower than trending diets in week 1. It’s faster than trending diets in month 12. By month 24 it doesn’t even compare — because by month 24 most trending dieters are back to baseline.